in reply to Error Message "Can't load 'C:/Perl64/lib/auto/DBD/Oracle/Oracle.dll" While Connecting to Oracle
I downloaded MSFT Dependency Walker> https://support.microsoft.com/en-us/kb/256872 .
Then opened auto\DBD\Oracle\Oracle.dll, and was shown which MSFT DLLs were the problem. (in this case Oracle DLLs were fine). Nice tool.