I have never used this program, but I don't believe the error is the "Warning: Tracefile events are not sorted by time." I think that is just a warning, letting you know that if you look through the tracefile, things may not be sorted by time. I believe the actual error is:
root@ubuntu:/home/pooja/Desktop/transmissionrange#Unknown Flag -1 in: + -t 48.464497912 -s 0 -d 1 -p exp -e 70 -c 2 -a 0 -i 727 -kd -1 -p ack -e 40 -c 2 -a 35 -i 592 -k AGT
My uneducated guess, you need to edit your wpan_demo1.tcl file. But as I'm not entirely sure what this is supposed to do in the first place, I could very well be wrong. Make backup copies before you edit though.