Web3js Error – Handling “web3.toWei is Not a Function”

The account can be created using the following command.

           web3.personal.newAccount(newPassword);

This method generates a new private key and stores it in the key store directory. The key file is encrypted with the given passphrase/password and returns the address of the new account.

Reference :- https://github.com/ethereum/go-ethereum/wiki/Management-APIs#personal_newaccount

web3 0.20.x is not using Promises, you need to provide a callback.

web3.eth.getTransactionCount(address, function(error, txCount) {
   // your code
}); 

ref