Invoque a program from a script.

I'm a dummie about UNIX scripts and I'm delighted for the answers I have found here. Thank's to all. Maybe in a far galaxy in other time I could give an answer or idea too :).
OK... I'm trying to invoque the program named lbrd_dochar from a script but it gives the mssg. "command not found" when the script is ran.
I suposse I must set an environmental variable or add a parameter to the script but I really don't know.
Do not hesitate to help me please.
JL

#!/bin/sh

. path_to_another_script_name

if you are using c shell:
#!/bin/csh

source path_to_another_script_name

HTH