This is a known corruption issue; please reference KM528123 to verify and fix the paths in the provided registry key (see below). If that doesn't work, might have to resort to a manual clean uninstall/reinstall using KM00319750.
1. Navigate to the registry key of the test object:
HKEY_CURRENT_USERSoftwareMercury InteractiveQuickTest ProfessionalMicTestTest Objects\Icons
2. (Optional/Recommended) Find a machine where the issue is not present.
3. Verify that the full paths of the registry values under this key are correct.
Example: The registry values under the above registry key for a web test object should look like: binWWWPackage.dll,,