I resolved this problem very simply.

Using nano as root i opened the file, which was DOS format.


DO THE FOLLOWING AS ROOT (OR SUDO) in a Terminal
=========================================

1) nano /usr/lib/frostwire/runFrost.sh

2) then save in nano CTRL+O

3) here you can hit ALT+D to change the format. Then hit enter to save the file.

Note:
make sure after hitting CTRL+O the filename it doesn't have [DOS Format] before it.

Frostwire should now work,

I wish the frostwire team would repack the DEB file, because everyone who downloads the latest frostwire (on linux) will have this issue.