error when attempting to add new host

[arthur sherman]

when attempting to add a new host, i get the error:

Could not find any object with id="-1394893198"

the quoted number changes along w/ the host i attempt to add.

a message "host successfully saved" flashes at the top right corner of the screen.

however, there's no sign of this host anywhere in adagios nor nagios (nor the cfg files).

i'm running adagios 1.6.1, nagios 4.1.1 on debian  (jessie)

any hints?

tnx,

ams