. . . . Can I use fastcut music in a commercial,or do I need to buy it with a commercial license from producerplanet? . . . .
You cannot use the music unless you have Commercial licences - a licence is required for every Soundpool used.
Do be aware that, when using Soundpools, if the commercial is for public broadcast ie on a web site, Youtube/Vimeo/other, local TV/radio station etc, then it is possible that you will get claims against you, from 3rd parties, alleging breech of copyright and/or plagiarism. This is unavoidable when you preset sound loops such as Soundpools.
I would advise you to take legal advice, before you proceed with putting the commercial live in the public domain.