1. type the argument:
Public Function BWT_Encode(CodeString As String) As String

I can't believe I forgot the type declaration!

2. re-dim the array:
Length = Len(CodeString)
ReDim TheStrings(Length)
Result = ""

Once again, how could I forget this? It's working beautifully after doing
this step.

3. Do you want the array to start at 0 or 1?

I assumed that VB string arrays start at 1 instead of 0, which seems to be
the way it's handled since the function is now giving the proper output of
"@nJ#osa" when fed the input of "#Jason@"

Thanks for your help, now that I've got the Encoding working, I'll work on
the decoding. (And hopefully remember to avoid the silly things I forgot
this time.)