CPG duznt work in post nuke it gives dis error when its installed plz help me

[FAT_PIZZA]

Fatal error: Call to undefined function: is_user() in /home/scrups/public_html/html/modules/picgallery/include/init.inc.php on line 37
can someone tell me how to fix this plz. . .  i installed da pic gallery like 10 times but still it gives da same error any tips or advices plz

[Joachim Müller]

post a link to the standalone and the one integrated into nuke