Informix 5.x error 246/105

I have been experiencing this error frequently on several different database instances. The error occurs on a simple select statement. Often, just running tbcheck -cD on tbcheck -cI solves it temporarily. I cannot seem to figure out what cauases this, and how to avoid it. Informix Support has been little to no help so far on this one. Got any ideas? Thanks a million... Mark Steele 74431.3327@compuserve.com