show_error crashing IIS 7

[eluser]Unknown[/eluser]
Any time I try to use show_error I get a generic 500 Internal Server Error instead of actual error output.

I've read that IIS needs "error_reporting = E_ALL & ~E_DEPRECATED" in php.ini but no luck.

The code I'm running is the example included with auth_ldap:

http://www.techrockdo.com/projects/auth_ldap

Thanks.