Having trouble solo mining I mine for fun. Please no responses saying "You really shouldn't mine on that computer. At all. Forget mining exists."

Whenever I try to mine using the instructions given in the README of the GUIMiner, it gives me an error as soon as the bitcoin.exe launches as a server.

Here's the error:

Invalid -rpcallowip subnet specification: *. Valid are a single IP (e.g. 1.2.3.4), a network/netmask (e.g. 1.2.3.4/255.255.255.0) or a network/CIDR (e.g. 1.2.3.4/24).
Try changing it to rpcallowip=192.168.0.0/24. Wildcard support was removed from bitcoind, more on reasoning here:

https://github.com/bitcoin/bitcoin/pull/4102 

rpcallowip=192.168.0.0/24is CIDR notation that is functionally the same as 192.168.1.*.