I received your zip file via e-mail, thank you.
I started with an empty workspace and then I imported your project from c:\home1 into my workspace while copying the project and when I start debugging it works fine, starting with vtb0169.cbl and then when I step through the program it steps into the called programs and debugs them just fine also.
What product version are you using?
I tested with Visual COBOL 2.1 update 1.
Thanks.