How to search "error." pattern with LOG

Hello,

I am trying to monitor a log file in order to be alerted when the string "error." appears.

For instance :

error.grammar error.noressource

... should send an alert

but "error " (with a space after) should not.

I tried to put in hobbit-clients.cfg :

LOG /tmp/log error. COLOR=yellow ==> does not work

LOG /tmp/log %(?-i)error. COLOR=yellow ==> works but match with error (without the .)

Does anyone can help me to find the correct regexp please ?

Thank you,

Vincent