Excel/POI The Final Frontier

First, thanks to all, particularly Scott Klement, for all your guidance. 
The spreadsheets I'm creating are perfect, just what the project requires. 
And reading them back in is even easier. Again, thanks to all.

Before I put out an email outlining what I've learned, I have just 1 more 
question (and 1 wish):

The question:
When running the workbook 'inbound' function, if there's a failure in the 
"book = HSSF_open(file_name)" loop because a given workbook in the group 
doesn't exist in the path, then no 'open' works after that even though 
subsequent workbook(s) in the group do exist. The monitor group around the 
'open' just prevents the halt, subsequent existing book(s) still fail on 
the open. I've tried "HSSF_end_object_group()" (in the on-error) but that 
fails as well. (I know the program logic is good because if I'm specific 
about the single workbook I want to read, it retrieves it just fine. What 
should I be doing after an 'open' legitimately fails? Or do I have to do 
an existence test in the IFS before I attempt the HSSF 'open'? 

The wish:
If there's a way to protect the sheet(s) of a workbook and the workbook 
itself (with a password) from within my creation program, I'll die a happy 
man.

Again, thanks for all your help.

Arthur J. Marino
Southern Container Corporation
(631) 231-0400 x133