Mystery lock being applied

We have jsut released a PowerBuilder application which user Informix 7.01 as the back-end and I have noticed that occassionally, rather infrequently, a table-level lock will get applied by the application. When we connect our isolation level is set to Committed Read and we also issue a SET LOCK MODE WAIT 10 immediately after connection. Nowhere in the application do we alter this locking strategy in code. I am wondering what can cause a table-level lock to get applied given the previous instructions. If I knew the potential situations under which this could possibly occur it would go a long way to helping us identify when and where this happens. So far we have been unable to reproduce this under a controlled environment or have been able to ask they user what was happening at the time they started seeing lock error messages. We believe it may be related to a query which uses invalid data-types for the specified column or something along those lines. Any help would be greatly appreciated. -- ------------------------------------------------------------ The opinions expressed are solely those of myself and do not represent the opinions or position of Fidelity Investments. Dave Voelker david.voelker@fmr.com ------------------------------------------------------------