Bethesda have replaced the Pitt download on Xbox LIVE after reports of some users having problems.The Fallout 3 download was causing crashes on some consoles and user are advised to delete their existing file and re-download.
To remove the faulty file choose the memory option in System Settings in the dashboard. Scroll to Fallout 3 and delete The Pitt file.
This is the second replacement file...
The Pitt costs 800 MSP (9.60 euro £6.80).
More on The Pitt here on gamezplay.org including video (age gate)