SOLVED
http://serato.com/forum/discussion/1010013#8304657
Okay guys, i have some great news for you, i have solved it,
It is an issue related to your window sound driver, not sure on mac, But i guess you mac user will figure this out after my windows direction, as we all know our setups where working, and then our phones and main outputs failed and we did nothing knowingly, but in my case i had just installed a separate Tascam audio interface,and ion my case i reckon it had changed my PC/Laptop sound setting, meaning it had taken over exclusive rights to out pioneer driver.
So i went into my windows sound settings and then the playback tab, i then selected the pioneer device and clicked the button bottom right to open properties, then in the the new dialogue box i selected the advanced tab, and unchecked exclusive mode, i do not know why i did not think of this early on, and those of us that have had issue with not being able to play for example you tube videos, at the same time as we have our music Daw open , will be aware of this situation,I cant believe i overlooked something so obvious.
So the same principles should apply to you all,some other hardware driver or windows driver, was stealing/locking out our pioneer driver, and as i mention, just unchecked Exclusive mode, this will allow drivers to share your laptop/PC sound resources
your issue 100% lies around your computer sound setting, not the pioneer driver or serato, unless of course you are exceptionally unlucky enough to have a broken unit.
So my apologies for my rant early on, it was frustrating times, sorry pioneer, sorry Serato.
I hope this helps you all, i have attached a screenshot for windows 7 for those that do not know what they are looking for.