Kim,
I just had the same issue, try this. ^_^
The file you downloaded from the company “gallery-wp-eStore.zip file” has the php file in it (gallery-wp-eStore.php)
I had the issue and noticed you may be experiencing the same problem as myself, the file you downloaded is labeled “gallery-wp-eStore” but the php extraction points to “gallery-wp_eStore.php”.
Notice the difference? The second file name has a _ instead of a -.
Basically, make sure whatever the error is pointing to – or _ that the file name in the view directory of nggallery is – or _ (whatever specified in the error).
I hope this helps!
^_^ have a splendid evening.
-Alex
