I've installed PHP4.3.0RC3 (altough, all 4.3.0 releases have te same problem).

I've set the php.ini file for use with the w32api extension.

But, it seem not to load the extension correctly.

The phpinfo() shows it is loaded:

Win32 API Support Enabled

But when I call one of the functions of the w32api, than I get a undefined function error.

This produces an undefined function error:
w32api_register_function ("User32.dll", "MessageBoxA", "long");

I've printed a function list with get_defined_functions(). An found none of the w32api functions.

I've even tried to load it trough dl() and tried it with apache 1.3.20 (sapi module), but the problem remains. 

After installing 4.2.2 again, everything work fine again.

Seem to me that there is something wrong there...