PHP3 Manual Prev Chapter 3.
Some problems are more common than others.
If you think you have found a bug in PHP3, please report it. The PHP3 developers probably don't know about it, and unless you report it, chances are it won't be fixed. If you are still stuck, someone on the PHP3 mailing list may be able to help you. You should check out the archive first, in case someone already answered someone else who had the same problem as you.