Clipbucket and ffmpeg on linux dedicated server

I have installed clipbucket and ffmpeg and all modiules on my linux dedicated server. I can convert very small files (10 meg) with clipbucket. On large files (150 megs) the upload just stops at about 10 or 15 %. The clipbucket installation says I need to install a later verion of ffmpeg. I can ftp large files to the server for manual processing, but clipbucket says it is processing the files, but never finishes. I need the server to be correctly setup, so I can install clipbucket on other domains on my server. I have a very small budget Thanks.