I have googled quite a bit but haven't been able to fix the issue. It might have something to do with an outgoing transcation from the Multibit wallet, that didn't go trought. It says under transactions "This transaction is not yet confirmed. Seen by 1 peer." The mentioned transaction was a very small transaction (around 2 dollars only) and is more than a month old. The value of of my actual wallet balance is many times the value of this unconfirmed transaction, so I don't see how this stuck transaction can block all my funds?
Any help is appreciated!
It can block your funds because of change. When you spend Bitcoin, you are actually not spending a balance of an address but rather transaction outputs. These outputs are like dollar bills, they can only be spent in full. In order to send the exact amount, you have to collect change, just like you would with dollar bills. This unconfirmed transaction could be spending from a large output and had to produce a change output. That change may be what is preventing you from being able to send more money because the change output is still unconfirmed.
Edit: Dang, shorena beat me to it.
thanks for the swift reply. Let's hope I can fix this mess I somehow cause..