I am trying to evaluate your product.
I have 2 machines with fresh installs of MySQL 4.1.10
The target maching has a fresh install of PHP 4.3.10 binaries for Win 32 (latest release of 4)
I can connect using MySQL client without a problem.
If I try to use HTTP tunnel, I get:
Error No. 1251
Client does not support authentication protocol requested by server; consider upgrading MySQL client.
Note that BOTH machines have the same version of both the MySQL server and client installed.