snap shot agent error - The replication agent failed to create the directory

Hi

i am getting following error with snap shot agent.

The replication agent failed to create the directory '\\192.168.2.4\sdb\snap\unc\WIN-EUK75GDCGAQ_SANKETUNIVERSAL_TEST2\20140307155950\'.

Access to that path is open. No security is set on that folder. If i go to run and type " '\\192.168.2.4\sdb\snap" it opens up the folder and can create delete modify files under this folder from any pc in network.

So any one can access it without permission. BUT still snap shot agent fail to run and give above error. It says" The replication agent failed to create the directory '\\192.168.2.4\sdb\snap\unc\WIN-EUK75GDCGAQ_SANKETUNIVERSAL_TEST2\20140307155950\'.

Folder is shared USB drive on NAS having no security.