Call to undefined function: vadmin_rc4_crypt()

Hi, Squirrelmail 1.4.2 serversidefilters plugin version 1.32, apache 1.3.26 and php 4.3.4, qmail/vpopmail/courier-imap, maildrop on debian stable. When the serversidefilters plugin goes to en/decrypt domain passwords using mcrypt, I get this error message: >>>> Fatal error: Call to undefined function: vadmin_rc4_crypt() in /var/www/squirrelmail-1.4.2/plugins/serversidefilter/backend.php on line 420 <<<< (line 420 when encrypting, 423 is when decrypting) The offending file is at http://feayn.org/backend.txt Now, lines 420-23 are controlled by >>>> if ($MCRYPT_ALGO == 'rc4_builtin') <<<< the 'else' to that if seems to open the specified mcrypt module and en/decrypt the input using that, bypassing lines 420-423 entirely. But but I get this error regardless of whether I set MCRYPT_ALGO to 'rc4_builtin' or 'blowfish' or whatever. My questions are: * Where/how should I define vadmin_rc4_crypt() * Why does php still die on lines 420-423 when the selection of an MCRYP_ALGO other than 'rc4_builtin' should bypass it? Sorry if this is plainly obvious, I'm totally new to php. Google has not been my friend on this one. Cheers, L