I tried to make a new library of all iTunes but PW couldn't play them.
Let's tackle this one first. Please explain exactly how you are going about this, just list the steps you take (1,2,3, etc.). Then I can try the same steps on my computer.
For example, here's what I would do if I wanted to import songs I usually play in iTunes into PMW:
1. On the main menu, go to File / Library / Import
2. Select "Import a single folder"
3. On the Media Import dialog, make sure "Audio" is checked.
4. Click the Browse button and navigate in Finder to the folder where the songs are located and click the Open button.
5. Click the Finish button and let PMW import these files. It won't actually move the song files anywhere, it just analyzes information about them and adds them to the PMW database (library).
6. Test playback of the songs in PMW.