This is my first post on the forums, and the first few days i'm using Inkscape, so first thanks to be able to use Inkscape!
My problem: i'm trying to make a ticket, something like this:http://th08.deviantart.net/fs71/200H/i/2012/065/d/f/ticket__boleto__de_admision_psd_by_gianferdinand-d4rz8lk.jpg.
However I'm experiencing problems cutting the round parts (left and right) of the rectangular object. I managed to do it once
This is what i was able to do:

So i managed to do it once, but now it isn't working anymore.
So what i have is:
- a rectangular shape for the complete ticket
- i made 1 circle and cloned it to make other circles. The one that was cut out was the original one. I made the circles on top by slecting and clicking 'home'
I tried to cut of the circles from the rectangular form by using Path > difference
If i select them both, then select paths > difference i get the message: one of the selected objects is not a path.
If I try to make path of both forms by CTRL+SHIFT+C it says 'no objects selected to make into a path'
Any suggestions on what I am doing wrong?
OR am I using the completely wrong method to get what i want?
thanks allready!