That all looks ok to me. I notice that /usr/bin/perl *does* support threads. What made you think it didn't ?

The other problem you mentioned in your original post was that Config.pm could not be found. Has that now been resolved ? What is the output of:

/usr/bin/perl -MConfig -e 'print $Config::VERSION'
[download]

and of:

/opt/perl/bin/perl -MConfig -e 'print $Config::VERSION'
[download]

Cheers,
Rob