Most routers/firewalls will not route UDP packets. U have a case where U need to talk to yar MIS guy/fellow to make it happen. Its a simple property-based on the hardware.
Also, the "ttl" on the packet dispatched also becomes critical, if Ur packets it jumping too many routers, it will eventually get dropped if ur "ttl" value is low.
Basically, its a network-issue; for which Ur MIS team will need to help U with.
Cheers.