Without a lot more info - I can't really begin to explore the error you have.
Are you fully synced? Is your balance correct. Check that you actually have a connection to at least 1 peer.
Are you pressing the correct shortcut to the wallet to open? Try opening it direct from the folder. You might be opening the old version? Check version number when wallet is open.
Does your wallet stake? And if its staking - turn staking off when you try and send.
Double check that the Cryptopia address is 100% correct
Post a screenshot of your wallet and the error mssg (blank out sensitive info)
Try Commission/fee of 0.01
Are you mistaken to send more UTC than you have? Send 2 UTC first as a test. (you should always do this anyway)
Make sure your AV program has not blocked anything related to the UltraCoin wallet.
Also - if your balance is from staking - its only spendable after a lot of blocks have passed (forget how many just at present). If the stakes are not returned/verified to balance - you will not be able to spend until they do.
Could be any number of other things - we need a few more clues to try and help you work out your problem.
I have several working and staking wallets and all are working perfectly.