Create Language plperl - Error: could not load library plperl.dll

When I create language plperl , I get error: *ERROR: could not load library "C:/Program Files/PostgreSQL/9.1/lib/plperl.dll": The specified module could not be found*. But in my computer, "plperl.dll" file is exist in "C:/Program Files/PostgreSQL/9.1/lib/..." folder ( I can not post illustrative image, this forum require >= 10 reputations) And if I select * pg_pltemplate, I get: -[ RECORD 4 ]-+------------------------- tmplname | plperl tmpltrusted | t tmpldbacreate | t tmplhandler | plperl_call_handler tmplinline | plperl_inline_handler tmplvalidator | plperl_validator tmpllibrary | $libdir/plperl