Cannot load new images after one failed image

[Beep6581]

Originally reported on Google Code with ID 2066

If RT fails to open an image (unsupported format in dcraw for example), it shows an
error dialog "could not load". After clicking okay the GUI is still responsive but
you can't open any images. Something is left in a bad state.

Test for example with this samsung raw which is not supported by dcraw:

web page: http://www.imaging-resource.com/PRODS/samsung-ex2f/EX2FLL016003.SRW.HTM
direct link: http://216.18.212.226/PRODS/samsung-ex2f/FULLRES/EX2FLL016003.SRW

Tested on Linux, RT 4.0.11.150

Reported by torger@ludd.ltu.se on 2013-11-19 11:36:35

[Beep6581]

Reproduced in latest in Gentoo 64. If I go to a different folder, the thumbnail placeholders
are drawnalong with the little rating and trash icons, but the thumbnails themselves
are not drawn, and I can select each but can't open any.

Reported by entertheyoni on 2013-11-19 18:57:33