Perl grep and Perl 4

Greetings, I'm using Perl 4 and have problems getting syntax error when using a grep BLOCK LIST. What I am trying to do is see if a string is in a list of strings, but using grep BLOCK LIST. Note, I have parenthesis in the string. This works in Perl 5 but not Perl 4: ... $string1="thisisstring(one)";