A 500 error when trying to log in

[rona]

i can logged in with a reseller or a customer account. but when i use a admin account, i received a error 500.

in the "default-error.log" file, it shows:
[Tue Jun 23 22:48:26 2009] [warn] mod_fcgid: read data timeout in 40 seconds
[Tue Jun 23 22:48:26 2009] [error] [client xxx.xxx.xxx.xxx] Premature end of script headers: index.php


and in the table "log" of database "ispcp", it shows i have logged in.

it seems an error is occured when the php script is trying to output something or maybe the communication between php script and daemon is abnormal

how can i fix this ???i am using freebsd 7.1