Heckman SPSS error

[gabriela.moreira.pereria]

HI:
I was trying to download the heckman command and I believe I managed to do it.
It's available now on the menu analyze/regression/heckman

However, when I try to run I always get this error message:

"Error in dirname(fpath) : a character vector argument expected"

Anyone know what it means?
Thanks in advance
Gabriela