If the commands are the same, the problem is likely with routing.
Check that you can reach the ftp server over the correct interface from root vdom, or look in the routing table of the root vdom (this is the management vdom in your case, can't run on a different one):
get router info routing-table detail 192.168.50.50
- Toss a 'Like' to your fixxer, oh Valley of Plenty! and chose the solution, too00oo -