InstallShield changed the way that setup.exe launched the _isdel routine, so that it became transparent to the self-extractor. Installshield seems to have addressed the issue with the /SMS switch.
The change made it so that the self-extractor does not see the ISDEL program being launched, due to the way that the setup program itself spawns the process. However, we've heard from a few users who have overcome the problem by including the /SMS switch with the command to issue.
Note: /SMS must be specified in uppercase
If you have any questions about this information, please submit a Technical Support ticket.
InstallShield Setup should not be in a folder