Tbcheck hangs OnLine 5.0 (UC3) engine

I have reported this problem to Informix tech support, but I have not yet gotten any answers, yet. The problem is that when I (we) run the tbcheck utility to collect extents, data & index page .... information, it hangs the OnLine engine. Tech support indicates that this problem was resolved in release 5.00 UC1. We're using 5.00 UC3. I cannot upgrade the server to a newer release of the software, because it is in a production mode. Has anyone else experienced this problem? Can I run the tbcheck utility from version 5.02 against the 5.00 engine? How about it Informix? Is there anyone out there? Btw, the information contained in the tbcheck utility is vital because we are currently sizing another database which is anticipated to be about 4 to 8 times larger. Any help is greatly appreciated!