I've got the same problem too - I just tried the suggestions in this thread, but still, it locks up the window I just tried to post in.
I've even done small posts before and it's frozen, and yet I've also done relatively large posts also and (finally) gotten through, without changing A THING.
I've also had extended periods with no problems, and others with constant problems.
Seriously - I have NO problems such as this kind with ANY other forums what-so-ever and I've experienced this problem on two different computers, each with completely different internet service providers, connection-type and hardware and software installed.
I'm convinced it's something to do with this message board - maybe not directly, but at the very least then, to do with compatibility issues.
"Someone's gotta get tough,
or someone else is gonna cry"