CompuServe Messages

To Technical support I am having difficulty creating a list box in a modal dialog box using THINK C. According to the THINK reference example a call is made to SetDItem with a handle to a user procedure. From this user procedure a call is made to setup the list box and a final call is made to SetDItem with a handle to the List. After a call to ModalDialog the dialog box is drawn correctly but is unstable. If the dialog box is moved (ie. movable modal dialog) the program crashes with a type 3 error. If another dialog is opened over the existing one a similar error results. Close inspection with the debugger reports an illegal instruction. SetDItem appears to cause the problem. According to THINK reference it appears to be related to a pointer problem but everything seems to be in order. Has anybody got any ideas what the problem might be, I have run out of ideas? Any Help appreciated, Darren Williams.