when u use comopen and open the COM object for custom objects and try to update them with a new version it wont allow it without restarting mIRC anyway to make mIRC stop using the DLL (incredible memory leak here)
(comclose doesnt work) ive even unregistered the comobject

This was also reported long ago Here.

As far as I can tell mIRC is correctly releasing the COM object and unregistering it, so I would guess that this is due to Windows itself holding on to it.

well as far as i can tell it doesnt work at all ive used every way you can to unload the class object etc. but it still holds onto it in memory (ive tried this in 3 languages now) so it cannot be working correctly the 3 languages are:
1: Delphi
2: C#
3: VB (and VB.NET)

(about to try it in J#)

Hey... I've been working with Acidized on this problem for a long time (We're both managers of #Script on irc.gamesnet.net - a 45,000+ person network).

As my origional post says, the file is still in use by a process, if you trace the file to its owning process, you will find that it is infact mIRC. As Acidized said, this is a HUGE memory leak issue and can provide insecurity for the application.