mingw g++ gives foreign language warnings instead of english ones

My problem is the following:

When I compile a C++ Project with eclipse (Juno, 64bit, Java 7u3) on my Windows 7 laptop, I get german errors/warnings. This results in warnings showing as errors in eclipse.

Windows (7, 64bit) is set to:

Display Language: English

Format: German (Switzerland)

Location: Switzerland

Language for non Unicode programs: English (Canada)

On my other Windows 7 (64bit) PC I have the exact same settings and don't have any problems.

I tried:

• Adding -Duser.language=en to the end of my eclipse.ini file.
  
  Which did not work


• Changing the Format to English.
  
  Which actually worked but is not
  really an option due to the wrong format in other places


• Many different things I can't remember (e.g. Environment variables in
  eclipse, etc.)
  
  Again, nothing helped

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