To anyone that comes across this thread as I did searching for a solution to this issue this is what worked for me – ffdshow.
I am using a particular codec that sort of works in premiere but that I found was giving a audio conform problem. After installing ffdshow it went away.
I installed version ffdshow_rev3631_20101115_clsid_x64.exe as this is a win7 64 bit version.
Basically ffdshow decodes your video files within Premiere. It handles the more esoteric formats that people use – like wma etc.
Just configure it when you install it (it’s part of the install process) to decode the formats you want to work with.
Try it, you can always uninstall it if it doesn’t work for you.
Drew