Try something like this.
You're not giving the correct information to ASCAN

Remove the semi-colon to allow the printer to install.

 Code:
If Not @LogonMode
  Break On
Else
  Break Off
EndIf
Dim $SO
$SO=SetOption('Explicit','On')
$SO=SetOption('NoVarsInStrings','On')
$SO=SetOption('NoMacrosInStrings','On')
$SO=SetOption('WrapAtEOL','On')


Dim $Users
$Users = Split("jdole:blee",":")

If ASCAN($users, @USERID)>=0
  ;$rc = AddPrinterConnection("\\ad2\hp4000")
  'Found User'
Else
  'Did not find User in array'
EndIf