[Observium] webpage showing "device" path not found

HI

I installed and configured observium as per the document mentioned on wiki . looks like everything is working and i got the web gui.I added 2 devices. it's showing 2 devices added and it's up.. But when i click on any of the hostname, it's giving the error like "404 the requested URL /devices/ was not found on this server

I check on the html directory and the device folder is not there. How to fix this isse.?

Thanks & Regards, Ben