Well recently i have completely reinstalled SuSE 9.1 because my hdd had a sudden death . Meanwhile i decided to install courier-imap and make a webmail for my users (not many - about 11).

Nothing wrong with the configuration and installing. The imap responds to a telnet on 143 dirtectly to my ip, so no problems so far.
The next step i took was to choose a webmail so squirrelmail was my choice. I downloaded the package, i planted it into my domain's folder and configuring it to function without ssl.
Well after setting all up - i just started a browser and paste the test link there : http://www.domain.com/squirrel-t01/ and look what i got :

Fatal error: Call to undefined function: session_id() in /path_to/www/domain/squirrel_t01/functions/global.php on line 293

I guess the problem comes from apache 2 (i'm using it) and it's cookie related or session related. Any ideea what went wrong? I have to mention that i'm using vhosts - so i have more than one domain and sub-domains on my webserver. Should i add something special in the conf regarding this domain between <VirtualHost> tags?

Thanks in advance.

Just a quick guess,

what php version do you use,
what version does squirel mail like to have??

Im using PHP 4.3.4 with SquirrelMail 1.4.3a ... and still have that error

... and yes i have pop3 and smtp installed else i couldnt install-configure imap succesfully...