1. Install mIRC in C:\mIRC
2. MOVE the mIRC folder in C:\Users\My user\AppData\Roaming\ to C:\ (it will ask if you're sure you want to, tell it yes)

This will put all of your install in C:\mIRC

3. UNZIP the omenserve 271 zip file to C:\mIRC
4. run OmenServe_Setup.exe (found in C:\mIRC)

You should have no more problems after this.

I use the following in various combinations (all working)
Windows 7 x64
mIRC v6.35 (installed in C:\mIRC) AND mIRC v7.14 (installed in C:\mIRC7)
OmeNServe v2.71
Invision 3.2 (July '10)

I refuse to engage in a battle of wits with an unarmed person. wink