what is 4.1 RC2?
forgive my ignorance
Dorin means download the latest candid release of Lightroom, its the next beta before the proper Lightroom comes out.
RC is Candid release or if you prefer almost perfect beta, they usually come out before the latest release of a program is sold to the public.
LR4 was / is troubled, so LR4.1RC1 came out with many bug fixes and issues resolved (that should have been resolved before LR4 came out)
LR4.1RC2 has many more improvements and Adobe have also intimated that the slowness of exporting to web and other issues will be in the final LR4.1
The link to download the LR4.1RC2 is here http://labs.adobe.com/downloads/lightroom4-1.html
Hope this helps
hope it works for you.
Try the LR4.1RC2 and see if that works.
Q - are you working from the Last Import folder, ie the reference to the lastly imported folder or the folder where the photos are?
If you are working in the Red folder, try working in the blue folder and see if that works.
If it does not, consider then making a bug report and then hopefully others will find the same problem.