Static DHCP IPs

I want to have static IPs assigned to various systems on a small network but when I added them to the static DHCP list I ended up losing DHCP all together so I had to delete them and all was good again. Any reason for this to happen? I want Untangle to give out the IPs on both wired and wireless but those devices get the exact same IP each time. Logical thought was to put them as statics with their MAC addresses or was I wrong? I am not sure why but we had a power outage and when it came back on DHCP would not work until I deleted all the static addresses. Any help would be appreciated. :worship:

Thanks

Greg