Applies to:

• All SDK (SMS API, STK API, etc.)
• all versions of SMS Engine — Enterprise Edition

Cause: “MSComm32.ocx” did not install properly or the date of the file is incorrect. This occur when MOBITEK SMS Engine — Enterprise Edition has been reinstalled a few times on the same Windows machine.

Solution:

1. Uninstall MOBITEK SMS Engine — Enterprise Edition.
2. Unregister “MSComm32.ocx”:
   1. for Windows 64-bit, run “cmd” or “Command Prompt” as “administrator”, then type
      1. “cd %systemroot%\SysWoW64\“
      2. “regsvr32.exe /u mscomm32.ocx“
   2. for Windows 32-bit, goto Start → Run → type “regsvr32 /u mscomm32.ocx”
3. Delete “MSComm32.ocx”.
4. Re-install SMS Engine — Enterprise Edition.

or

1. Unregister the “MSComm32.ocx” and delete it
   1. for Windows 64-bit, run “cmd” or “Command Prompt” as “administrator”, then type:
      1. “cd %systemroot%\SysWoW64\“
      2. “regsvr32 /u mscomm32.ocx“
   2. for Windows 32-bit, goto Start → Run → type “regsvr32 /u mscomm32.ocx“
2. Copy the new “MSComm32.ocx” and manually register it:
   1. for Windows 64-bit, run “cmd” or “Command Prompt” as “administrator”, then type:
      1. “cd %systemroot%\SysWoW64\“
      2. “regsvr32 mscomm32.ocx“
   2. for Windows 32-bit, goto Start → Run → type “regsvr32 mscomm32.ocx“

source: https://support.microsoft.com/en-my/help/249873/how-to-use-the-regsvr32-tool-and-troubleshoot-regsvr32-error-messages