SQL & PL/SQL

I've been looking all over trying to figure out why I'm getting this error and can't figure it out. I'm just trying to make a table to keep track of unique hits on a page so the table looks like this with a select * from HIT_COUNTER:

url counter id
---------------------------------- ---------- -----
test.htm 0 1
http://localhost:8040/test.jsp 0 2

I am having trouble updating my counter field. When I try
UPDATE HIT_COUNTER SET counter = 1 WHERE url = 'test.jsp'
I get
ORA-00904: "URL": invalid identifier

It's obvious that the "url" field exists, so why do I get this error?

Thanks for any help

*edit, I'm having trouble getting the formatting to look correct in the select results, but I think you can get the idea