Hi cazz,
A few tips:
1. You mentioned using notepad++, did you set EOL ( End of Line ) markers to Unix format and then saved the file ? Check Google if you are unable to locate this option in Notepad++
2. You can also use the command dos2unix filename on Linux to convert it to Linux format and then run it and check.
3. if it does not work still, other options are :
a. call bash full_path_to_file_name in the dialog command
b. instead of a script, try to make it single line, using ; between commands and supply it to your dialog command directly
Hope this helps. Please try all of these options and let us know which one works.
Regards,
Nathan SR