and then use electrum to import private keys. 
Electrum should not be used with imported keys. Just keep using Multibit and everything will be fine or send the bitcoins to a new wallet with a normal bitcoin transaction.
I thought has has some problem when using Multibit, that's why I said to import private keys to Electrum as I couldn't find any better wallet. If there is no problem, then I suggest you to continue with Multibit.
~~MZ~~