pidgin.dll

Doesn't McAfee give you an option to ignore it or add an exception (assuming the detection is a false positive)? Maybe your computer is genuinely infected. I have no such problems with Pidgin, and I use it daily. However, I don't use McAfee.

Pidgin is the only instant messaging software I use and McAfee Security Center [Antivirus - Firewall] and I have never encounter any problem.

The only pront I get from McAfee is from the Firewall asking me to grant online access to PidginPortable.exe and this is just a rule that changes when pidgin is updated.

Also, in none of my virus scan results has "pidgin.dll" come up as a threat.

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Now after a short search on Google I found this thread

https://portableapps.com/node/8808

It looks like they had this problem back in 2007.

I don't know what version/type of McAfee you are using but I am using the VirusScan Enterprise Edition [Business] with Intrusion protection. In it's default configuration it blocks IRC communication, by port blocking I believe.

Perhaps your version is set to block instant messaging clients in a similar way?

Go into the VirusScan Console and see if you have an option for:
"Access Protection".
If you do, open it and see if it has:
"Prevent IRC communication" checked for both Both "Block" and "Report".
If so, try unchecking "Block", if that does not help set it back to block.

You might see if you have some other setting set to high that could block outside communication.

I'm not saying this is your problem, but it's worth a try if other things don't work.

Tim