Tested on Cog's SVN 33437 on two machines, XP Pro and Win 7 32 bit

scenario.
Using the open icon on the image input node (in composite nodes) and the select the images you want using the B hotkey to lasso them, Or, use the A key to select them all. you get these messages.

Can’t read ‘R:\Other\results\’, Invalid argument (win 7 reading images over network)

Can’t read”//test\client\results\”, No such file or directory (XP Pro reading native drive)

This happens if you do not first select a file with the mouse.

But, if you first select a file and then press A or use the B key to lasso there is no problem.