I just resyncd the whole chain - no errors in daemon anymore.
BUT wallet still says, that there are no transfers (list_transfers), no balance (balance) and a reset doesn't change anything.
current bc_height 29076...
PLEASE HELP!
mining also does not work anymore...
I want the old version back.

That's weird. Reset usually takes few minutes to rescan all blocks.
Close wallet, stop daemon. Open wallet, reset, close wallet. Run daemon again and once it is up open wallet and give it a few minutes to scan the chain.
2018-Jan-18 19:55:49.450566 ERROR Error: Failed to invoke rpc method: HTTP status: 1