I am having a problen copying flash to TFTP

This is what happens on the router:

PRO2621#copy flash tftp
Source filename [c2600-ik9o3s-mz.122-11.T1.bin]?
Address or name of remote host []? 10.121.252.8
Destination filename [c2600-ik9o3s-mz.122-11.T1.bin]?
……
%Error opening tftp://10.121.252.8/c2600-ik9o3s-mz.122-11.T1.bin
(Timed out)
PRO2621#

Any ideas? Am I doing something wrong?