Undefined Variable error message

I fixed this myself by changing the code in "brilliant_gallery.module" starting at line 269 the code was:

if ( $captionyesornot == 'yes' or $captionyesornot == '' or ( variable_get('brilliant_gallery_caption', '') <> '' and $captionyesornot <> 'no' ) ) {
             $showcaption = 'filename';
           } else if ( $captionyesornot == 'no' ) {
             $showcaption = '';
           } else {
             $showcaption = $captionyesornot;
           }

I changed it to:

 if ( $captionyesnotext == 'yes' or $captionyesnotext == '' or ( variable_get('brilliant_gallery_caption', '') <> '' and $captionyesnotext <> 'no' ) ) {
             $showcaption = 'filename';
           } else if ( $captionyesnotext == 'no' ) {
             $showcaption = '';
           } else {
             $showcaption = $captionyesnotext;
           }

Of course the offending variable is changed from "captionyesornot" to "captionyesnotext"

Worked for me!