i'm workin' with VBE (visual basic excel).

i've several userforms linked one with the other
in each object of the userforms (command buttons i.e.) i've writed some
lines of code.
i use many local variables as indexes for my cycles.
I HAVE NOT initialized none of them and on my PC everything works right
!

i've send my file to one of my testers and he told me he can't run
macros involved because variables are not initialized.

1st question: how could that be possible ?? maybe different version of
VB &/or EXCEL ??

2nd question: how could i initialize all variables without acting in
EVERY SINGLE button containing a cycle or a local VARIABLE ?

3rd question: is it possible to declare all variables involved once in
a time? (i.e. launchin a macro that declare all variables kind makin
them acting as GLOBAL VARIABLES)

really thanks 4 answering!