Friday evening, anyone going into Item-IN-A or B, is now getting the Fatal error described above.  The error message says "The field you are trying to use is unallocated.  It may belong to a file that hasn't been opened yet or was an array that was removed from memory - BKAP.PO.NUM".  Only response is "OK".  As you select the "OK" button, the message just pages through all the BK files (BKVEND,....etc).  Upon further discovery today, we get this error on any screen we go into and try and do a look.  Only way to stop is "alt-ctl-del" and end session.  
 
However, when signing back into Evo, we get the series of error messages as follows: "CODEBASE ERROR", Error:1210, Error: 83801, Transaction Error, Invalid transaction file - run recovery utility C:\ISTS\TASPRO7.LOG.
 
SSSSoooooooo.  What's going on

I spoke with our MIS people and they indicated they have not had any problem with our server.  This started happening at approximately 3:00pm Friday afternoon (01/23/09).

Val,  spoke with Lynn and she figured we had a damaged BGLUGRID.* file.  We replaced from a known good backup source and everything now is okay.  
 
Thanks for your help.
 
Dennis