Synopsis
In calling some function, you specified an empty string (ie, two quotes with nothing inbetween), but the function requires something more. name is the function you called which is complaining about the empty string. number tells which arg was an empty string (where 1 is the first arg).
Cause
You wanted to specify your arg as a literal string, but you forgot to put quotes around it. Therefore, Reginald assumes that it is the name of a variable which contains the real value. And that variable was previously assigned an empty string.
Cure
If you're directly supplying your arg as a literal string, put quotes around it.