What do you think you're accomplishing with:

if($1, $2, $3, $4) {
[download]

? I think you probably mean either:

if($1 or $2 or $3 or $4) {  # any of $1..$4 is not empty
[download]

or:

if($1 and $2 and $3 and $4) {  # all of $1..$4 are not empty
[download]

Liz