Mumble is another program people use with swtor.
Try doing a clean boot http://support.microsoft.com/kb/929135
Make sure McAfees has launcher.exe and swtor.exe in the exception list.
Try turning off programs like PunkBuster that you are currently running in case of conflict.
Try turning off indexer
1 > open Search, select the "Indexing" arrow and set it to "do not turn on"
2 > run services.msc and double click the "indexing service", set it to disabled and reboot.
Delete DiskCacheArena File then run a defrag before playing again.