JAShank

I am using Express Scribe Pro v. 5.56 on a Windows 8 computer. I am trying to load a mp3 file that is over 6 hours when I pull it up in Media Player but can only get 5 minutes and 12 seconds to load in Express Scribe. I have uninstalled, reinstalled, upgraded to Pro from the free version and nothing is helping. It is definitely a mp3 file. Any suggestions?