Since this is a windows error, you need to determine which version of perl an XS module was linked against without loading it. Anyone have any ideas on how this might be accomplished?

MSVC (2005):

> dumpbin /dependents MD5.dll

[snip]
  Image has the following dependencies:

    perl510.dll
    KERNEL32.dll
    msvcrt.dll

[snip]
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I saw a web page suggesting there may have been a "depends.exe" in some other version.

MinGW (e.g. Strawberry Perl) and assuming you have grep for brevity:

> objdump -x MD5.dll | grep "DLL Name"

       DLL Name: perl510.dll
       DLL Name: KERNEL32.dll
       DLL Name: msvcrt.dll
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