I just updated (using wget) to the afni version 2.55c of 06 Aug 2003.
The plugin did not automagically popup when I select "Dataset#2" from
the Tran 1D menu.
(I am using AFNI/bin/linux_gcc32/afni on redhat 9.0 platform).
But, anyway I can view the orig data and the fitted data overlaid now.
Thanks for the help.