print is a fabulous debugging tool. Show us what $val and $df are: 
use warnings;
print " Enter the dilution factor. \n";
 chomp ($df = <STDIN>);
 open FILE, "45well.txt" or die $!;
 while (<FILE>){
 chomp $_;
  @values = split('\t', $_);
  $val = @values;
  foreach $val (@values){
print "df >>>$df<<<\n";
print "val >>>$val<<<\n";
 $DNA_conc = $val * $df * 50 ;
 print $DNA_conc;
 print"\n";
 }
 }
 close (FILE);

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That's Tip #2 from the Basic debugging checklist.

In reply to Re: handling tab delimited files by toolic
in thread handling tab delimited files by shaludr

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