All my sites are on same ip. Could that become a problem?

I have a hosting account in which I can put just about unlimited websites on it for a set price per month. The sites are all on the same ip. Is that something that can hamper my seo efforts in the future? I see no problems so far. Im asking because I was reading up on some class c ip stuff and not being on the same class c...etc etc..Im not really sure that stuff applies to me in this case.

It will not be a problem as long as you are not dropping some blackhat shit on
any of your sites and you are not interlinking.
If you interlink you will get no benefit but if you do blackhat you risk getting
all your sites de-indexed if they are interlinked.

So when you interlink, you have to make sure they are on different servers?

No problems with that. Just don't interlink them. That would make things just too obvious to Google.