So, if I understood correctly, I would have to add all of these 30 or so DLLs manually in the PP command line?
No, not all 30, you're probably only missing libbgd.dll , should be located somewhere near where you installed perl or cygwin or mingw
In general, you don't add the .dll's that come with the operating system , stuff under %WINDIR%, %windir%\system32, like kernel32.dll user32.dll gdi32.dll comdlg32.dll advapi32.dll shell32.dll mciole32.dll ole32.dll oleaut32.dll netapi32.dll ws2_32.dll cmprops.dll mpr.dll mprapi.dll mprddm.dll mprdim.dll mprmsg.dll mprui.dll winmm.dll version.dll odbc32.dll odbc32gt.dll odbccp32.dll comctl32.dll
$ perl -V:libs
libs=' -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 -l
+advapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmp
+r -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32 ';
kernel32.... they all come from microsoft with windows