The latest remote debugger I can find on the Nusphere site is for PHP 4.3.1. I'm running PHP 4.3.3. Can I use the 4.3.1 debugger module on my server or is there an updated debug module?

Yes, indeed, the debugger shipped as a standalone update is for php-4.3.1 and below. This update pack is intended for PHPED 3.1 only. Current version of PHPED is 3.2 and it contains debugger modules for all php versions in range from 4.0.6 up to 4.3.3. See debugger subdirectory.

So essentially what you're saying is that despite having purchased this product less than a year ago, Nusphere wants me to pay an additional $300 to use remote debugging with the current version of PHP?

You probably have purchased phped 3.1. In this case you have debugger version 2.12.7 with modules for php 4.3.0 and below. So you can work with php 4.3.3 (current version of php) using dbg.so-4.3.0 as all subversions of php 4.3.x share the same API.
NuSphere certainly does not want you to pay any additional $$ for that.

Ahhhh...I see. So I CAN use the 4.3.0 debugger with PHP 4.3.3. Thanks for clearing that up. I'm much less aggravated now. So I should be able to use the following versions of the debug extension with PHP 4.3.3:

dbg.so-4.3.0
dbg.so-4.3.1

I have both, so I'm going to try the 4.3.1 version unless there's some reason I should use the 4.3.0 version instead. Thanks again for the help.