Thanks for the response. I'll compile 0.9.56 for use tomorrow and see how it goes. I tried the lines you mentioned with 0.9.55 but only got the line. fixme:wintab32:X11DRV_WTInfoW Return proper size This line seems to appear whenever one of the sub windows in openCanvas is clicked. I don't think it's related to the problem. There is also lots of the following, although they appeared before I used the WINEDEBUG line, and appear when almost anything happens in the program. I don't think it's related to the problem, but I'll post it just in case. fixme:bitblt:X11DRV_ClientSideDIBCopy potential optimization: pixel format conversion And then the stacktrace and debug information if/when the divide be zero happens.