...snip...
You may be hitting a number of files open limit. It should continue
past that error. But it won't be able to log errors to the error table.
Can you try it logged in as root or get the number of open files/process
increased a little on your system?
Does:
gw -st "select NAME from SYSTABLES"
show the error table?
Does:
gw -st "select * from error"
work? (It may not print anything if the table is empty, but it
shouldn't cause any error messages either).