strawberry 5.20 comes with DBD-Oracle installed

I overwrote the existing Perl installation with Strawberry 5.20 to have a current release.

An old strawberry? Did you delete existing one first or really overwrite? If you did not delete existing first, you should do that :)

But it doesn't have a compiled DBD-Oracle either. It would be weird if it did. Because... how would some other guy know where my Oracle client has been installed?

And thats nonsense

http://strawberryperl.com/release-notes/5.20.0.1-32bit.html#distlist says 107. DBD-Oracle 1.74

installing strawberryperl 5.20 means you're done

After downloading some libraries from the internet or copying them from the server (eg OCI.dll) to the Perl/bin directory I now seem to be having a compiled Oracle.dll file. But...

Nope, thats not good , thats why you get error message

Looks like the file is corrupt...

Nope, its your mixing stuff ... if its not all in %PATH% it won't be found (or if the wrong thing is in the path first ... worst case its Re^2: Error Message "Can't load 'C:/Perl64/lib/auto/DBD/Oracle/Oracle.dll" While Connecting to Oracle (not valid))

strawberry 5.20 comes with DBD-Oracle installed