Index: src/app/qgshandlebadlayers.cpp
===================================================================
--- src/app/qgshandlebadlayers.cpp	(revision 15380)
+++ src/app/qgshandlebadlayers.cpp	(working copy)
@@ -26,6 +26,7 @@
 
 #include <QDomDocument>
 #include <QDomElement>
+#include <QUrl>
 #include <QPushButton>
 #include <QMessageBox>
 
@@ -102,8 +103,7 @@
       }
       else if ( provider == "delimitedtext" )
       {
-        QStringList theURIParts = datasource.split( "?" );
-        filename = theURIParts[0];
+        filename = QUrl::fromEncoded(datasource.toAscii()).toLocalFile();
       }
       else if ( provider == "postgres" || provider == "sqlanywhere" )
       {
@@ -296,9 +296,10 @@
       }
       else if ( provider == "delimitedtext" )
       {
-        QStringList theURIParts = datasource.split( "?" );
-        theURIParts[0] = filename;
-        datasource = theURIParts.join( "?" );
+        QUrl uriSource = QUrl::fromEncoded(datasource.toAscii());
+        QUrl uriNew = QUrl::fromLocalFile(filename);
+        uriNew.setQueryItems(uriSource.queryItems());
+        datasource = QString::fromAscii(uriNew.toEncoded());
       }
     }
     else
Index: src/core/qgsmaplayer.cpp
===================================================================
--- src/core/qgsmaplayer.cpp	(revision 15380)
+++ src/core/qgsmaplayer.cpp	(working copy)
@@ -24,6 +24,7 @@
 #include <QDir>
 #include <QFile>
 #include <QFileInfo>
+#include <QUrl>
 #include <QDomDocument>
 #include <QDomElement>
 #include <QDomImplementation>
@@ -179,9 +180,12 @@
   }
   else if ( provider == "delimitedtext" )
   {
-    QStringList theURIParts = mDataSource.split( "?" );
-    theURIParts[0] = QgsProject::instance()->readPath( theURIParts[0] );
-    mDataSource = theURIParts.join( "?" );
+    QUrl url = QUrl::fromEncoded(mDataSource.toAscii());
+    QString file = url.toLocalFile();
+    file = QgsProject::instance()->readPath(file);
+    QUrl urlNew = QUrl::fromLocalFile(file);
+    urlNew.setQueryItems( url.queryItems());
+    mDataSource = QString::fromAscii( urlNew.toEncoded());
   }
   else
   {
Index: src/plugins/delimited_text/qgsdelimitedtextplugingui.cpp
===================================================================
--- src/plugins/delimited_text/qgsdelimitedtextplugingui.cpp	(revision 15380)
+++ src/plugins/delimited_text/qgsdelimitedtextplugingui.cpp	(working copy)
@@ -133,7 +133,7 @@
 
     // add the layer to the map
 
-    QString uri( url.toEncoded() );
+    QString uri = QString::fromAscii( url.toEncoded() );
     emit drawVectorLayer( uri, txtLayerName->text(), "delimitedtext" );
     // store the settings
 
Index: src/providers/delimitedtext/qgsdelimitedtextprovider.cpp
===================================================================
--- src/providers/delimitedtext/qgsdelimitedtextprovider.cpp	(revision 15380)
+++ src/providers/delimitedtext/qgsdelimitedtextprovider.cpp	(working copy)
@@ -150,7 +150,7 @@
     , mWkbType( QGis::WKBNoGeometry )
 {
 
-  QUrl url = QUrl::fromEncoded( uri.toUtf8() );
+  QUrl url = QUrl::fromEncoded( uri.toAscii() );
 
   // Extract the provider definition from the url