Below is the .conf file, ddclient only seems to be updating the last address on the list. In this case "Site 5".
daemon=600
protocol=namecheap
use=if, if=eth1
server=dynamicdns.park-your-domain.com
login=Site 1
password=#####################################
@
protocol=namecheap
server=dynamicdns.park-your-domain.com
login=Site 2
password=#####################################
@
protocol=namecheap
server=dynamicdns.park-your-domain.com
login=Site 3
password=####################################
@,www,mail
protocol=namecheap
server=dynamicdns.park-your-domain.com
login=Site 4
password=#######################################
@,www,mail
protocol=namecheap
server=dynamicdns.park-your-domain.com
login=Site 5
password=######################################
@,www,mail
Are you sure you are using 3.8.0? According to the report we received, 3.8.0 should work correctly, 3.8.1 has some issues.