Error 500 in a ecommerce CMS

[ftp21]

Hello,
A customer when try to send an email by his script, if he set to send 900emails at 100 for time all is good if he send all 900emails in one time he receive this error:

2012-03-08 16:34:04.722 [INFO] [X:12025-0#APVH_X] Connection idle time: 301 while in state: 5 watching for event: 25,close!
2012-03-08 16:34:04.722 [NOTICE] [X:12025-0#APVH_X] Content len: 1811, Request line: 'POST /shop/adminpanel/mail.php?action=send_email_to_user HTTP/1.1'
2012-03-08 16:34:04.722 [INFO] [X:12025-0#APVH_X] Cookie len: 83, zenAdminID=fa9d4fa4f0b98a59ad56ae0743b88fae; zenid=500f89a66041b7a3a10d2b48eea2d6c0
2012-03-08 16:34:04.722 [INFO] [X:12025-0#APVH_X] HttpExtConnector state: 8, request body sent: 1811, response body size: 0, response body sent:0, left in buffer: 0, attempt
s: 0.
2012-03-08 16:34:04.722 [INFO] [X:12025-0#APVH_X] Lsapi connection state: 2, watching event: 25, respState: 1, m_iTotalPending:0, m_iPacketLeft:0, m_iCurRespHeader:5, req se
nt for 301 seconds,Total processing time: 301.

I use LS 4.1.11, how i can fix this?

Waiting for your reply

Regards

[NiteWave]

how long will it take to send out 900 emails ? over 5 minutes ?

try to increase
Server->Tuning->Connection Timeout (secs)
default is 300 seconds.