|Don't delete it, this is an important part of ActiveX, removal of this could be detremental to your system. plugin.ocx purpose is related to Netscape plugins in Internet Explorer among other things.|
The error message your get is obfucstrated to say the least and clearly doesn't identify what the 'issue' is.
There have been reports of heap overflows, spyware and malware among other things effecting this file, but your 'Crap Cleaner' has no right to advise anything to be done with this file. Just download the Microsoft Update.
If you experience any specific issues with ActiveX then you can re-download this file. Either individually or by a package installation.
Hope that answers your question, sorry about the belated reply, been busy at work so I have been writing the answer fragmentedly.
There are 10 sort of people that exist in this world, The ones who understand binary and the rest