Hmmm? This is puzzling. So I can tell you that originally you are issued 2 pass-keys. One key will let you post and vote but it will not let you do anything with your wallet or voting for witnesses.
For that, you must use the other pass-key which will let you do everything, including transfer funds and vote for witnesses.
This is a built in safety feature that Steemit offers to give anything to do with tranferring currency an extra level of protection.
Here's something to try:
go to your wallet page. Across the top, you will see "Balances" "Permissions" and "Password".
Choose "Permissions" This will show you all your pass-keys. The first is your posting key, the next one is your active key (Transfers currency and witness voting) and then there's a Master key which lets you change the 1st two pass-keys. Lastly, there is a memo key and this is the one that you want to use if you want to send a memo along with a currency transfer. This is very important because you never want to use your active key to send a memo because people can see your key and you can be hacked.

Now, this piece is also confusing: Once you start looking at your pass-keys you will see that you must "click" on the "show private key" box or the "login to show"box to reveal "your actual" active key.
If you copied the posting key without clicking on "show private key" you'll be trying to use a generic key that isn't yours. I think it just holds space as an example, but it's confusing.
Do you think this is what you have done?