Help! BSOD in Unix

[Barry Wiseman]

SunOS
filepro 5.0.14

These people win the cake for most weird problems I'm seeing for the 
first time in 30 years of filepro.

Today, they suddenly stopped being able to load *clerk or *report.  I 
launch the program from the shell, no arguments, it never gets to Enter 
Filename.  Redraws the screen blank in filepro's background color, and 
hangs with the cursor at 0,0.  Does not respond to BREAK or Ctrl-\. 
Only a "kill -9" from another terminal will recover the session.

Creation programs, dxmaint, ddir all run fine.  Only these four.  The 
*clerk and *report binaries are checksum identical with those on the 
test server, which run fine there.  Permissions and ownerships all look 
correct, both in $PFPROG and $PFDIR trees.

Ideas?