i think i have found the source of the trouble.the software bring used for the site is not defined to be used on the latest php version. i think when i updated the sever the php version was updated causing an issue.
Operating system Ubuntu Linux 10.04.4
ISPConfig Version: 18.104.22.168
Webmin version 1.580
Kernel and CPU Linux 2.6.32-40-server on x86_64
Processor information AMD Phenom(tm) II X4 945 Processor, 4 cores
Real memory 4.0 GB total