what does this mean. plz help

Not sure.

If you're American, maybe the apology would be for bombing the place.

"Stay on trails" could mean keep on the tourist trails which would be safer, or it possibly could be a reference to unexploded anti-personnel mines.

Just a guess.

Tag is probably on the right track (no pun) but maybe staying on the trails keeps you out of areas contaminated

http://www.google.ca/#hl=en&output=search&sclient=psy-ab&q=vietnam+chemical+weapons&oq=vietnam+chemical+weapons&gs_l=hp.3..0j0i8i30l3.1997.7855.0.8081.24.18.0.6.6.0.264.2164.3j13j2.18.0.les%3B..0.0...1c.1.k1H4Y4AA9X4&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=b3fdf32aa7af5abf&bpcl=36601534&biw=1395&bih=838

thank you so much!

thank you !

You're quite welcome. Your response is welcome in this otherwise convoluted conation of insensate redoubt