Lucas:

shell is almost self-explanatory . You should read the shell interpreter to interpretate what interpreter says to you.

Either you compiled or downloaded a linux or windows version of Forknote, you should have this four executables "forknoted, miner, simplewallet, walletd".
find the file simplewallet (remember if you are using it in Linux it must have a x attribute) and replace simplewallet with full path to the file.
That's all!
If you are running this sentence in the same directory/folder you have simplewallet then you must add ./ in front of it to tell bash you want to execute the simplewallet in relative path.

Just to be curious and don't take it bad, please, but you want to build a pool, have you at least some knowledge on basis. What will happen if you have some issues with redis or something that you cannot handle?. if the pool will be public you should consider this. Remember you are dealing with third-party's "money"