Cannot move files to trash

My problem is that I can't drag a file to the trash. When I try to delete a file by right-clicking and choose "move to trash" I get a message telling me that the item will be deleted permanently and that I cannot undo this action. In other words it is possible to delete a file permanently, but I would like to have the option to move them to the trash first.

I have recently tried to partition the internal hard-drive using Boot Camp, however unsuccessfully. I don't know if the two are related.

I have Macbook 13,3" early 2010 with the latest version of Snow Leopard, 10.6.4.

Thank you.