When Poser launches, I get an error that says: NULL (or empty) script name to PEPhython engine. I installed the Reality fix and the startup script that came with it. So how do I fix this?

I assume you mean AVFix? by snarlygribbly.

where did you install the scripts?

did you follow the instructions during install?

IMPORTANT: The installation requires you to make changes in the Runtime within the folder in which you installed Poser.
Depending upon on your operating system, and where you have installed Poser, you may need to perform these steps with Administrator privileges.

STEP 1
    
    1.0 Create a folder called Snarlygribbly in the Runtime/Python/poserScripts/ScriptsMenu folder
    1.1 Copy the avfix.pyc file into the Snarlygribbly folder

    When you have done this you should have this file in your runtime:
    Poser SoftwarePoser 11RuntimePythonposerScriptsScriptsMenuSnarlygribblyavfix.pyc

STEP 2 (OPTIONAL)
    
    NB: This step is ONLY NEEDED if you have addons (such as Reality) that need to use this fix.

    2.0 Copy the included poserStartup.py file into your Runtime/Python/poserScripts folder, overwriting the existing one.
    
    (NB: If you have modified your poserStartup.py then (a) make sure it is backed up first and (b) modify it by adding lines 5 to 9 from the included poserStartup.py)

Yes, the AVFix, and I followed all the instructions, both steps.

is the startup script in the same runtime as your snarlygribbly folder? ?

I seem to have 3 startup scripts. One is in Runtime/Python/poser Scripts/Scripts Menu along with the Snarlygribby folder. the other is Smith Micro/Poser 11 and the third is in Runtime/Python/poserScripts.