We are having some problems with comments right now. You cannot write any Urdu in the comments or even use single or double quote signs (smart or otherwise). Basically you cannot use any non-ASCII characters in comments.
This seems to be related to the recent upgrade of this weblog to Movable Type 3.34 and MTValidate 0.5. It is probably a result of this blog being the only Movable Type blog running native Unicode.
We are working on fixing this soon.
UPDATE: I have temporarily fixed it by reverting to MTValidate 0.4. So comment away!