I sent that question because probably I know where is a problem but now I need to be sure.
My version of phpwcms is 1.2.8 realse 25.08.2006, php version is 5.1.4 and apache 2.0.55
It works fine on my own computer but after installation on some hosting provider server, strange things happed.
After login to phpwcms for about 5 to 10 seconds all is fine but after that period an when some link is clicked it returns me to the login page. After short investigation checklogin.php.inc was found

My questiion:
Is there any solution to avoid this problem ?