>  the "Gem.dll: couldn't load" appears in the console.
loading with log set to "all" might give you a more specific error here

Do you mean in -verbose mode? Here is the output when trying to load Gem:

tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem-94/Gem.m_i386 and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem-94/Gem.dll and succeeded
E:\jmmmp\elektronik\pd-vanilla\extra\Gem-94\Gem.dll: couldn't load
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem-94/Gem.pd and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem-94/Gem.pat and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem-94/Gem/Gem.pd and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem.m_i386 and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem.dll and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem/Gem.m_i386 and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem/Gem.dll and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem.pd and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem.pat and failed
tried C:/Users/user/AppData/Roaming/Pd/Gem/Gem.pd and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem.m_i386 and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem.dll and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem/Gem.m_i386 and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem/Gem.dll and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem.pd and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem.pat and failed
tried C:/Program Files (x86)/Common Files/Pd/Gem/Gem.pd and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem.m_i386 and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem.dll and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem/Gem.m_i386 and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem/Gem.dll and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem.pd and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem.pat and failed
tried E:/jmmmp/elektronik/pd-vanilla/extra/Gem/Gem.pd and failed
 Gem
... couldn't create