I have never heard of MVI... do you mean MOV?
The key is... what codec is inside that MOV wrapper?
Read Bill Hunt on a file type as WRAPPER http://forums.adobe.com/thread/440037
What is a CODEC... a Primer http://forums.adobe.com/thread/546811
What CODEC is INSIDE that file? http://forums.adobe.com/thread/440037
Report back with the codec details of your file, use the programs below... a screen shot works well to SHOW people what you are doing
If you have a red line over the timeline after importing a video and before adding any effects... your project is wrong for your video... read above about codecs
Once you know exactly what it is you are editing, report back with that information... and your project setting, and if there is a red line above the video in the timeline, which indicates a mismatch between video and project
Also, if you are talking about a HiDef camera... your old Premiere 6.5 is not likely going to work... but, what is the exact codec?
I found this link which explains what mvi files are it also says that premier does not open them although I thought perhaps at some stage a Premier version would be updated to import these file considering that the Canon cameras shoot the video in this format