LaserSoft Imaging

We have have an epson 1640xl transp w/ firewire scanner. The first G3
mac we used this with was running os 8.6 with Pshop 5.5 and silverfast
Ai 5.1 ,silverfast would always crash in"batch mode(file)" but we could
successfully use "batch mode"

Now we are running newest version Ai 5.5 with G4 and are getting
inconsistent scan densities in HDR batch modes ......1st scan in batch looks
great -all additional scans are about 2 stops too dark! all prescan
previews look fine. Batch mode (file) will crash 50% of trials . This
is occuring in Ai 5.2.0v05 also. We have 400mb of ram allocated to Pshop
6.0 on this unit.

In addition to the above post:
I have trashed Sfast and reloaded the program to try to eliminate any possibility of corrupt software.

Any ideas Lasersoft ?????