To create a dumpfile from svn, use the svnadmin tool. The command should be something like:

svnadmin --deltas dump /path/to/repo | gzip > dumpfile.gz

If your data is currently in CVS, simply create a tar or zip file of the entire directory (it should have a file called CVSROOT in it). To tar a file, you can use tar: 

tar cjf dumpfile /path/to/cvs

Please note that large attachments will bounce, so do not attach your dumpfile but rather send us a link to it, upload it to the webdav area included with your account or ftp it to ftp.wush.net using your master account username and password as credentials.