Net.data and/or SQL and record locks

Hey all,

Today I wrote and tested a simple lookup net.data macro.  my sql
selects from two files joined and displays the results.

This afternoon, I found one of my cgi request processor jobs had a
lock on one of the files.  The last thing the joblog had in it was an
sql syntax error telling me that /filename was wrong - ('/' was not
expected - my library variable was not filled in).

There were several others in there, but all of them were sql syntax
errors that would have stopped the statement from running and thus
shouldn't have locked the file.

I guess my question is, what would cause an sql statement to remain
locked to a file, after it runs to completion or bombs?

Thanks,

Rick