can not find channel error on puts

CL v5.8, Sun, Solaris 10. Using testing tool for a tclproc.

Trying to use a variable in ChannelId for a Puts command.

Example: ChannelId should be:  fr_op_file_region_13

This works:    puts  -nonewline $fr_op_file_region_13   $hold_rec_type01

This doesn’t:  puts  -nonewline $fr_op_file_region_$fr_pcms_region   $hold_rec_type01

Pertinent tclcode:

       set fr_op_file_region_13 [open $path/hl7oru_to_hl7fr_region_13x.txt w]

   

       if {$fr_rec_type == “02”} {

           set fr_pcms_region [csubstr $fr_ip_rec 56 2]

                    echo “+++ region : ” $fr_pcms_region

           if {[lsearch -exact $region_list $fr_pcms_region] >= 0} {

                    echo “+++ lsearch good, region : ” $fr_pcms_region

           } else {

                    echo “+++ lsearch bad, region : ” $fr_pcms_region

                  }

       }

           if {$fr_rec_type == “02”} {

                     set ZZZ fr_op_file_region_$fr_pcms_region

                     echo “+++ ZZZ: ” $ZZZ

               puts -nonewline $ZZZ $hold_rec_type01 <

---

fails here

                                                               

       

       close $fr_op_file_region_13

       

Testing tool results:

+++ region :  13

+++ lsearch good, region :  13

+++ ZZZ:  fr_op_file_region_13     <

---

value looks correct

[0:TEST] Tcl error:

msgId = message0

proc = ‘fr_region_split’

args = ”

result = ‘can not find channel named “fr_op_file_region_13″‘

errorInfo: ‘

can not find channel named “fr_op_file_region_13”

   while executing

“puts -nonewline $ZZZ $hold_rec_type01”

   (procedure “fr_region_split” line 94)

   invoked from within

“fr_region_split {MSGID message0} {CONTEXT sms_ib_data} {ARGS {}} {MODE run} {VERSION 3.0}”‘