hacked guestbook (please help) *don't know how to fix it*

someone please help me. I can see my guestbook entries if I do this individually

http://www.phyrstamendment.com/guestbook/

[09-Mar-2005 09:51:43] PHP Parse error: parse error, unexpected T_CHARACTER, expecting T_STRING or T_VARIABLE or T_NUM_STRING in /home/phyrst21/public_html/guestbook/lib/gb.class.php(101) : eval()'d code on line 3

[10-Mar-2005 23:42:16] PHP Parse error: parse error, unexpected T_CHARACTER, expecting T_STRING or T_VARIABLE or T_NUM_STRING in /home/phyrst21/public_html/guestbook/lib/comment.class.php(51) : eval()'d code on line 3

I can see still see all my guestbook entries if I do this

http://phyrstamendment.com/guestbook/comment.php?gb_id=63

i cannot get into my admin at all

http://phyrstamendment.com/guestbook/admin.php

someone please help. i'm not too familiar with .php

my files are there but how do I get them back? how do I fix my guestbook?