[Plugin: Feedfabrik Blogbook Printing] made site go down

i don’t know if my site was php4 or not,
but when i added it it was working fine,
but next day when i tried to log in nothing worked!!
i could not even log in ,
i saw a message says feedfabrik:authenticate.
pluggable.php error and stuff like that,
once deleted evruthing was working fine.