If you get an error when starting your shellnode follow these steps:

• shut down the wallet
• change masternode=1 to masternode=0 in conf file and start wallet again
• send the 25,000 SHELLS to a "fresh address" in your wallet. And in console use: dumpprivkey "fresh address"   to get the masternodeprivkey
• copy the new privkey and shut the wallet down
• in conf change the mastenodeprivkey to the new key you just got and masternode=0 back to masternode=1
• start the wallet back up
• make sure you have 7 confirms on your masternode address and in console type: masternode start