issue with deleting and moving files / directories

Some facts in advance:

Macbook Pro 13 inch (medio 2010)

2,4 GHz Intel Core 2 Duo

Software Mac OS X Lion 10.7.5

There is a problem with deleting a bunch of files and directories. Sometimes putting them in the bin is a problem, sometimes that works fine.

If it doesn't work properly the system is hanging in the window showing putting the files into the bin. No message of error.

I often have to force-stop the finder since nothing is happening.

I first wanted to delete a lot of files and directories, but now even deleting empty folders is a problem.

Then deleting the bin is somewhat the same story, sometimes that works allright and then with another file the system keeps hanging in trying to delete.

Then I tried to move the items to a usb-stick trying to get rid of the items in another way. The same problems.

I had run the disk-check-utility: first there was a problem, but I fixed that via recovery-mode (start-up with command - r, run diskutitlity).

I did the PRAM-reset.

I did the remove the trash via terminal rm -ri ~/.Trash

Still the same problems occur.

Anyone????

Bas