Thanks for the pointers to ListDlls and other stuff. But any solution for "check a DLL for other DLLs it references" that would be acceptable for PAR::Packer would have to restrict itself to use only stuff that is already present on the platform or whose existence may be inferred from the fact that PAR::Packer was buildable on this machine (e.g. C compiler + related toolchain stuff).
On Windows that would mean something that comes with VisualStudio (if you used that to build PAR::Packer) or with the MingW toolchain (e.g. that comes with Strawberry Perl or can be installed on ActivePerl with the "mingw" pseudo PPM). Cheers, Roderich