[ns] Error with xgraph visualization in wireless examples

[ALBERTO FELIPE PEREZ <alberto.felipe@upcnet.es>]

Hi all,
I'm working with ns-allinone-2.1b7a under Red Hat Linux 6.2 and when I try to run a file .tr (with "xgraph filename.tr" ), that I obtain from the wireless examples,  the next error message is shown: 

*************
....
Error in file `wireless3-out.tr' at line 4817:
Unknown line type
Error in file `wireless3-out.tr' at line 4818:
Unknown line type
Error in file `wireless3-out.tr' at line 4819:
Unknown line type
....
....
***************************
However  I can visualize other .tr files  correctly, but not the wireless files.
What can I do to solutionate this problem?
Thank you .