The DHCP pool must start outside of the manually assigned range (in your case DHCP range should start from .103
But this probably doesn't solve your problem with the manual assignment not working. Did you enter the MACs without any ":" or "-" between the hex numbers? Should look like this in the webinterface: 001122334455, not like this: 00-11-22-33-44-55 or 00:11:22:33:44:55. (Actually I'm not even sure if the webinterface lets you enter wrong values, have no firmware to check it )