Problem uploading large amount of files.

hello,
In my web site there's a need to upload allot of pictures at a time.
for some reason every once in a while there is an error message which says something like "please contact the web master".
I didnt find any documentation about this error, any clue what should I do?


here are some of the parameters i use

var iu = new ImageUploaderWriter("ImageUploader1", 650, 400);
iu.activeXControlCodeBase= "Aurigma/ImageUploader5.cab";
iu.activeXControlVersion = "5,0,30,0";

iu.javaAppletCodeBase = "Aurigma/";
iu.javaAppletJarFileName = "ImageUploader5.jar";
iu.javaAppletCached = true;
iu.javaAppletVersion = "5.0.30.0";
iu.showNonemptyResponse = "off";
//Configure appearance.
iu.addParam("PaneLayout", "TwoPanes");
iu.addParam("ShowDebugWindow", "true");
iu.addParam("AllowRotate", "true");
iu.addParam("BackgroundColor", "#ccccff");
iu.addParam("TimeOut", "3600000");
//Configure thumbnail settings.
iu.addParam("UploadThumbnail1Width", '<%#PictureUploadKind.PictureUploadWidthT1%>');
iu.addParam("UploadThumbnail1Height", '<%# PictureUploadKind.PictureUploadHeightT1%>');
iu.addParam("UploadThumbnail1JpegQuality", '<%# PictureUploadKind.PictureUploadQualityT1%>');
iu.addParam("UploadThumbnail2Width", '<%# PictureUploadKind.PictureUploadWidthT2%>');
iu.addParam("UploadThumbnail2Height", '<%# PictureUploadKind.PictureUploadHeightT2%>');
iu.addParam("UploadThumbnail2JpegQuality", '<%# PictureUploadKind.PictureUploadQualityT2%>');
iu.addParam("MinImageWidth", '<%# PictureUploadKind.PictureUploadMinWidth%>');
iu.addParam("MinImageHeight", '<%# PictureUploadKind.PictureUploadMinHeight%>');