http://bugs.winehq.org/show_bug.cgi?id=25305
--- Comment #5 from Tristan Schmelcher tristan_schmelcher@alumni.uwaterloo.ca 2010-11-27 03:36:39 CST --- I stepped through the 16-bit installer machine code between the DdeConnect() and the error dialog and this is the sequence of Wine calls:
DdeConnect DdeCreateDataHandle -- fails at the check for pInstance == NULL DdeClientTransaction -- fails at the check for pData == NULL in WDML_ClientQueueExecute DdeDisconnect
Then many hundreds (possibly thousands) of instructions later it calls MessageBox to display the error dialog.