Windows 7 went Beta 1 officially to Technet and beta testers on Wednesday evening during the Ballmer keynote speech at CES.
Today, Windows 7 beta 1 will be available publically to 2.5M people that download it through the Microsoft website.
The OS is feature complete, what it has or doesn't have now is what it's going to have when Windows 7 actually gets released. So the error message received will continue to occur even on the final version.
I've brought it to the attention of Microsoft. Also to the attention of the mIRC developers so they're aware of it and can work out a solution or think of one now for when it's released.
That is all.