When you tried to install BB 407 you were installing a gingerbread ROM.
BB351 is a Froyo ROM. There have been some reports of problems reverting from GB to Froyo.
I suggest that you use fastboot to flash:
- The recovery for BB 351 or BB 360
Then reboot to recovery and try installing the update.pkg.
For some reason some Streaks need the baseband files flashed first before the Froyo ROM will install properly. This happened with my Streak when reverting from GB.