I´ve de same problem but i could solve it. (first im sorry about my poor english is not my natural language)
I´ve 2 memories. I copy the first memory, the BPAV folder entirely. And the second memory only the clips folders into CLPR directory in the directory that i´ve created in the first memory in my hard drive.
I make this in one computer and a i have not problem importing the mp4 archive into premiere cs3 3.2.
But the problem was in other computer. I give the same steps but premiere says unsuported format…. etc. i could read the first memory archives but not the second because i dont copy the entire BPAV folder. But the difference was that the second computer has not installed the software from sony XDCAM EX ClipBrowser. It´s free. I installed the software on the second pc and i open the folder with this software, only open not recompress, i could import all de mp4 archives into premiere cs3. That works for me.
Again, sorry about mi poor english and good luck for all.