Error -259, too many open cursors ?

Here's an error to test everyone's memory. There's a user in rural NZ who's using a version of Informix Turbo v3.??. (Plexus DataManager) who is getting error -259 (cursor not opened) on a fetch statement. The fetch that the errors occurs is within a cursor that also opens other cursors, depending on values etc. They have a number of processes, server and client that are acting against this table. I don't have the exact info yet but it appears to be occuring on the UNIX process every 65th time, and on the DOS - windows client every 27th. This leads me to suspect a file open limit. I seem to remember a bug about cursors and open file limits can anyone else recall it ? TIA - Wouldn't it be nice if everyone upgraded ???