'open a folder'
Do you mean in Windows Explorer? Like expanding the tree in the left pane until you see the subfolders in My Pictures, then clicking on such a folder?
Please quote the full and literal text (without typos) of the error message. 'wiamgrdeviceslenght' isn't known to google, so I assume it's something else.
But start with a scandisk to see if that finds any errors in the folder structure and repairs them. If that doesn't help, post again with more info.
i am unable to open any of 'my pictures' folders..the following window appears [wiamgrdeviceslenght is null&void]