PM offers.

Note to members interested in these domains:

"Participants may not instruct users to check your e-mail, check your PM, or inform them that they've got mail or a new PM, or any variant thereof. This rule is also applicable in the advertising forums."

What did I do wrong? I don't understand.
Is this the case of "or any variant thereof"?

No, you're fine. The intention behind that rule is to stop a few dozen "PM sent" messages appearing. Folks are more than welcome to PM you as you've requested.

Cheers

Gary