Welcome to the forum ApHuNtEr!
The cause of the (false positive) virus warning is a very basic DLL included in Invision. It is NOT a virus at all, but can be
used by a virus for various IO functions, so occasionally some anti-viruses pick it up.
I am planning on removing the DLL from Invision because of this at some point in the future. In the meantime, I have made a 7zip containing all the Invision files (excluding the DLL), available here:
Just download that and extract it to your mIRC directory, making a back-up prior to that if you want. Overwrite when prompted. Also, if on WinVista or newer, make sure the "Users" group has write permissions to the mIRC directory. If you are unsure how to do this, you can just move the entire directory to My Documents or your Desktop.
With this 7zip, Invision will run nearly completely without issue. One or two very rarely used features may not work without the stdio.dll file, but that's nothing to worry about. If you have any further questions or issues, feel free to post again, or visit us in #Invision on irc.irchighway.net!
Good luck, and enjoy Invision!
Edit: Virustotal link for the 7zip file:
https://www.virustotal.com/en/file/ad73 ... 426888357/0/50 detections, since stdio.dll is only thing that some anti-viruses seem to have an issue with.