[PyMOL] Pymol recolour B factors

Hello,

I'm trying to recolour the B factors in a pymol file with chemical shift 
differences (from NMR data). There's a nice script here for this 
http://pldserver1.biochem.queensu.ca/~rlc/work/pymol/ (data2bfactor.py) and 
also a simpler one here 
https://figshare.com/articles/Pymol_script_loadBfacts_py/1176991.

In both cases after loading the script with the run command, when I execute 
the script I get the following error

data2b_res 1d3z.pdb, shift_to_b.txt
Selector-Error: Invalid selection name "1d3z.pdb".
( 1d3z.pdb )<--

The pdb file and list of new b-factor values are in the same directory and 
can be filled in with tab-completion. I've also tried using the full file 
path but get a similar error. I've tried with a couple of different pdb 
files as well so it's not just a problem with that particular pdb file.

I'd be grateful if anyone has any experience with this or suggestions as to 
what is going wrong.

Thanks in advance,

Mark