You have not "received this error" as yet.

The warning Useless use of private variable in void context at makefile.pl line 595. is down to

# Following generates
# Useless use of private variable in void context at Makefile.PL
# but is required
$rv;
[download]

in the Makefile.PL and you do not need to worry about it.

You should read the warnings in DBI about running a thread enabled perl especially if you intend writing perl code that uses threads.

If you are not on Windows you also need to be aware of the difference between thread-safe and non-thread-safe ODBC drivers because thread-unsafe drivers won't work with a perl using threads.

All these warnings came out because your perl is built threaded and hence you could run perl code using threads. Things get complicated when you do that. If you do not intend to run any perl code using threads you can ignore this entirely.

Press a key and it will continue to process a Makefile and you can build it.