Index: lib/tdom.tcl
==================================================================
--- lib/tdom.tcl
+++ lib/tdom.tcl
@@ -946,10 +946,17 @@
         }
         set absolutURI [uri::resolve $base $systemId]
         array set uriData [uri::split $absolutURI]
         switch $uriData(scheme) {
             file {
+                if {$::tcl_platform(platform) eq "windows"} {
+                    # Strip leading / for drive based paths
+                    if {[string match /?:* $uriData(path)]} {
+                        set uriData(path) [string range $uriData(path) 1 end]
+                    }
+                }
+                # FIXME - path should be URL-decoded
                 return [list string $absolutURI [xmlReadFile $uriData(path)]]
             }
             default {
                 error "can only handle file URI's"
             }
@@ -962,22 +969,27 @@
 #   
 #   A simple convenience proc which returns an absolute URL for a given
 #   filename.
 #
 #----------------------------------------------------------------------------
-
 proc tdom::baseURL {path} {
-    switch [file pathtype $path] {
-        "relative" {
-            return "file://[pwd]/$path"
-        }
-        default {
-            if {[string index $path 0] ne "/"} {
-                return "file:///$path"
-            } else {
-                return "file://$path"
-            }
+    # FIXME - path components need to be URL-encoded
+
+    # Note [file join] will return path as is if it is already absolute.
+    # Also on Windows, it will change \ -> /. This is necessary because
+    # file URIs must always use /, never \.
+    set path [file join [pwd] $path]
+
+    if {$::tcl_platform(platform) ne "windows"} {
+        return "file://$path"
+    } else {
+        if {[string match //* $path]} {
+            # UNC path
+            return "file:$path"
+        } else {
+            # Drive based path
+            return "file:///$path"
         }
     }
 }
 
 namespace eval ::tDOM { 

Index: tests/dom.test
==================================================================
--- tests/dom.test
+++ tests/dom.test
@@ -1052,11 +1052,11 @@
     set doc [dom parse -useForeignDTD 0 {<root/>}]
     $doc delete
 } {}
 
 test dom-4.2 {-useForeignDTD 1 with document with internal subset} {need_uri} {
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set ::tdom::useForeignDTD "data/domCmd1.dtd"
     set doc [dom parse \
             -useForeignDTD 1 \
             -baseurl $baseURI \
             -externalentitycommand ::tdom::extRefHandler {
@@ -1069,11 +1069,11 @@
     $doc delete
     set result
 } {toThat}
 
 test dom-4.3 {-useForeignDTD 1 with document with internal subset} {need_uri} {
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set ::tdom::useForeignDTD "data/domCmd1.dtd"
     set doc [dom parse \
             -useForeignDTD 1 \
             -baseurl $baseURI \
             -externalentitycommand ::tdom::extRefHandler {
@@ -1087,11 +1087,11 @@
     $doc delete
     set result
 } {toThis toThat}
 
 test dom-4.4 {-useForeignDTD 1 with document without document declaration} {need_uri} {
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set ::tdom::useForeignDTD "data/domCmd1.dtd"
     set doc [dom parse \
             -useForeignDTD 1 \
             -baseurl $baseURI \
             -externalentitycommand ::tdom::extRefHandler <root/>]
@@ -1100,11 +1100,11 @@
     $doc delete
     set result
 } {toThis}
 
 test dom-4.5 {-useForeignDTD 1 does not overwrite a given external subset} {need_uri} {
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set ::tdom::useForeignDTD "data/domCmd1.dtd"
     set doc [dom parse \
             -useForeignDTD 1 \
             -baseurl $baseURI \
             -externalentitycommand ::tdom::extRefHandler {
@@ -1120,11 +1120,11 @@
     set result [catch {set doc [dom parse -useForeignDTD foo <root/>]} errMsg]
     lappend result $errMsg
 } {1 {expected boolean value but got "foo"}}
 
 test dom-5.1 {document with external subset} {need_uri} {
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set doc [dom parse \
             -baseurl $baseURI \
             -externalentitycommand ::tdom::extRefHandler {
 <!DOCTYPE root SYSTEM "data/domCmd2.dtd">
 <root/>}]

Index: tests/domNode.test
==================================================================
--- tests/domNode.test
+++ tests/domNode.test
@@ -3022,11 +3022,11 @@
 
 test domNode-34.1 {getBaseURI} {need_uri} {
     makeFile <y/> domNode-34.1-e1.xml [file join [file dir [info script]] data]
     makeFile <y/> domNode-34.1-e2.xml [file join [file dir [info script]] data]
 
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set doc [dom parse \
                  -baseurl $baseURI \
                  -externalentitycommand ::tdom::extRefHandler {
                      <!DOCTYPE x [
                                   <!ENTITY a SYSTEM "data/domNode-34.1-e1.xml">
@@ -3054,11 +3054,11 @@
 
 test domNode-34.2 {getBaseURI} {need_uri} {
     makeFile <y/> domNode-34.1-e1.xml [file join [file dir [info script]] data]
     makeFile <y/> domNode-34.1-e2.xml [file join [file dir [info script]] data]
 
-    set baseURI file://[file join [pwd] [file dir [info script]] dom.test]
+    set baseURI [tdom::baseURL [file join [pwd] [file dir [info script]] dom.test]]
     set doc [dom parse \
                  -baseurl $baseURI \
                  -externalentitycommand ::tdom::extRefHandler {
                      <!DOCTYPE x [
                                   <!ENTITY a SYSTEM "data/domNode-34.1-e1.xml">