Invalid pointer error during Detection center initialization in Anti Spam Setup Wizard

Symptoms

When enabling the Anti spam module via the Setup Wizard, I receive an invalid pointer error during the detection center initialization.
Invalid Pointer

Resolution

This is due to MSXML4.dll becoming unregistered when uninstalling ISA server. This can be resolved by re-registering the MSXML4.dll as per the steps below:
  1. Open the Start menu and click on Run
  2. Type cmd in the run dialog box and press enter
  3. Type cd %systemroot%\system32 in the command prompt window and press Enter
  4. Type regsvr32 MSXML4.dll and press Enter
  5. Click OK to the "DllRegisterServer in msxml4.dll succeeded." information box
  6. Rerun and complete the Mail Utilities Setup Wizard...