Yes, but it's difficult to figure out because it's a size limitation. You can't have more than 32K (32 kilobytes) of rules.
That means you should be able to have 50-60 rules. If they're complex, however, you may not be able to have that many. The more complex the rule, the bigger its size.
For information on creating rules, please see Creating a Rules. You'll need the free Adobe Reader to view it.