A very good effort, but do you need Perl to do this? =)

You might consider using smbmount with credentials in fstab instead of username and password, which solves the local echoing of the password. Essentially, what you do is create a file with two lines:

username=Username
password=Password
[download]

somewhere in /etc. You then make sure owner and group are root, set permissions to 400, and add the credentials=/etc/yourfile to your options column.

//windowsbox/windowshare /mnt/win smbfs noauto,credentials=/etc/yourfi
+le 0 0
[download]

You should also consider setting UID/GID in the options as well, to make sure that the unprivileged user mounting the share can also write to it.

Cheers,

--
Allolex

(update) PS: You need to chomp() your variables to get this script to work.