I tried your issue with a 30000 row DataTable and could not reproduce your issue, could you provide more info on the type of data, maybe post a stack trace of the issue?
If you have a compact sample, you could submit it to Developer Support and let them debug it as well.
Simply copy/pasting the stack trace may provide additional clues. Other than that, you can try ViewState management and switch viewstate persistance to one of four possible locations:
As demonstrated in the following forum threads:
This may alleviate the problem or provide additional clues.