Server cannot be accessed by a certain LAN IP

[16-bit]

I've had this issue where any workstation that gets the IP of 192.168.7.149 cannot connect to our fileserver (192.168.7.3). Windows firewall is disabled with no third party in place, no funky routes or IPsec policies and I've checked the switch for any rules/errors but there's none. has anyone had this issue before?

 

[16-bit]

Oops I left a fair bit of info out of that!

To answer some of the questions:
The fileserver is windows 2003 and the workstations I've tried are xp/7
It's indeed a flat network on the same subnet.
.149 is reserved in dhcp to another device which is using another IP(so it wouldn't allocate it to another device). I'll just exclude it from dchp.
Cannot ping or connect on any open ports either way.

 

[16-bit]

Ah, it was the arp cache! Ta very muchly Pete!