hello all
i am installing leach protocol in ns 2.34

but i got some error.

can't read "env(RCA_LIBRARY)": no such variable
while executing
"source $env(RCA_LIBRARY)/ns-ranode.tcl"
(file "mit/uAMPS/sims/uamps.tcl" line 9)
invoked from within
"source.orig mit/uAMPS/sims/uamps.tcl"
("uplevel" body line 1)
invoked from within
"uplevel source.orig[list $fileName]"
invoked from within
"if [$instance_ is_http_url $fileName] {
set buffer [$instance_ read_url $fileName]
uplevel eval $buffer
} else {
uplevel source.orig[list $fileName]
..."
(procedure "source" line 8)
invoked from within
"source mit/uAMPS/sims/uamps.tcl"
(file "tcl/mobility/leach.tcl" line 18)
invoked from within
"source.orig tcl/mobility/leach.tcl"
("uplevel" body line 1)
invoked from within
"uplevel source.orig[list $fileName]"
invoked from within
"if [$instance_ is_http_url $fileName] {
set buffer [$instance_ read_url $fileName]
uplevel eval $buffer
} else {
uplevel source.orig[list $fileName]
..."
(procedure "source" line 8)
invoked from within
"source tcl/mobility/$opt(rp).tcl"
(file "tcl/ex/wireless.tcl" line 187)

i have read all of the comments by deepa and heloys...
n tried all the steps by deepa.....
but i have a doubt at post no. 75

"i think there was something else i did ... check the tcl-object.tcl file. I remember i followed instructions from there.

Got it !
You need to set the variables in \tcl\lib\ns-default.tcl"

please explain me where i have to change in file ns-default.tcl....
because all the variables are already set into ns-deafault.tcl