I ran your code with no problems. What are the errors you seeing? Is it something like:

synsun1000
Can't open synsun1000: Invalid argument at D:\Sysad-perl\perltest\test
+1.pl line
13.
Can't call method "login" on an undefined value at D:\Sysad-perl\perlt
+est\test1.
pl line 14.
[download]

If that is similar to what you are getting then the problem is that your second system is not available or does not exist.

If not, you might consider puting an availability check if your systems are not always up.

update

Another passing thought from looking at your code. I see "ntsrv" if they are nt servers, they have to have the FTP deamon running. So best bet is to show the error you are getting.