I am not aware of any file size limitations. Your 68 meg file should have worked as far as I know.

Please give more details on the warning message you got. Exact text would be nice, and a description of when and where it appeared. Was it on the player, in emplode, what?

The file name does not survive the trip to the empeg. The only limitation on the file name is that it must be a valid Win32 file name so that emplode can actually find the file and upload it. Emplode gets all of its data from the track's tags, not from its file name.

There is a known bug in 2.0b3 regarding excessively-long comment tags in files with ID3v2. Does the file have an ID3v2 tag with a long comment field?