Problem pasting text into editable PDF Form using Preview...

I am attempting to simply fill out an editable PDF form (using Preview), but am unable to paste text without the lines of text overlapping after I have pasted it into the form. It will look perfect originally, but as soon as I click to another area in the PDF, there is no longer any space between lines in a paragraph. What is up with this? It's not as if I am pasting too much text to fit into the designated form area...in fact, it all looks great until I move my cursor to another section. Totally frustrated!!! Please help - or recommend another program I can use for Mac OS X Lion (preferably shareware since this is a ridiculously simple feature for a PDF editor/reader to have). I attempted to work-around this issue using Preview's annotation capabilities, but frankly - it's a PITA using these features in a form with pre-made text boxes.