Unzip Command in tcl

I attempting to create a tcl proc that unzips a file in a certain directory.  Here’s the code.

proc rac_837_unzip2 { args } {

  global HciSiteDir

  echo “HCISITEDIR=>$HciSiteDir<" set test_dir “$HciSiteDir/data/ssi_837_cl” echo ” TEST DIRECTORY IS ” $test_dir exec cd $test_dir exec unzip 837.zip } I have a upoc thread setup using advance scheduling.  I keep receiving an error:  unzip:  cannot find or open 837.zip, 837.zip.zip or 837.zip.ZIP.’ The 837.zip files does exists in that directory.  Any suggestions?