Been here, seen this, fixed this.  Actually we found the solution on the
Knowledge base but the answer in the knowledge base is wrong.  Sorry, I do
not remember the KB solution number, but this is what you have to do.

The default in the Device\Parameters section for the Qlogic card defaults to
0x21.  The KB says to change it to at least 131 from 21.  What it meant to
say is 131 decimal.  We set it to 255 or 0xFF and now the SAN agent works
fine.  The issue is the tape header blocks are read/written as one on the
SAN agent apparently differently than the server.  The result is what you
see.  The keyword to set is MaximumSGList.  Sorry I cannot remember the HKEY
for this.