[Elecraft] "ant err pr flt" error message?? also antenna adjacency problem??

[Julie Royster]

Hello all, we just got back our KX3 after under-warranty repair.
The technician included a message that the parts he replaced were usually
damaged if
1)	Connected to an antenna during a thunderstorm (nope, not here)
2)	Power over 100 watts on "an adjacent antenna"
		
QUESTION 1:  The KX3 has been using an inverted V wire antenna.  At its
closest point to a vertical antenna for our K3 they are about 30 feet apart.
Is this too close?  How far away would be far enough if K3 operator were
using 450 watts?    I do recall one morning when I used K3 while Larry had
KX3 on.  I guess I will never do that again, but I would like to know what
distance is safe.  We have a neighbor a block away who runs high power.

QUESTION 2:  I just set the KX3 back up with KXPA100.  When Larry
transmitted at 5 watts all was OK but when he transmitted at 40 watts it
said "ANT ERR"  at the top of the screen and "PR FLT" at the bottom.
I checked the connections.  I checked the SWR of the antenna with a SWR
meter.  What do these messages mean (as they are not described in the
manual)?
Could these messages have to do with the KXPA100?

THANKS to anyone who can opine.
73,
Julie KT4JR