Visual Studio requires my assembly to be "strong-named"

I'm getting this error when I try to run my add-in for Microsoft Word.

Could not load file or assembly 'Word, Version=1.0.0.1, Culture=neutral, PublicKeyToken=null' or one of its dependencies. A strongly-named assembly is required. (Exception from HRESULT: 0x80131044)

The assembly Word.dll is built from another solution and is referenced to in my addin to the file itself. The Word solution also has a few references within that solution.

When I try to run my addin I get the error above. I've tried signing the assembly and its depending assemblies, but the same issue persists. I've checked the GAC to see if there was some old assembly installed there, but no luck there either.

Why does it require this assembly to be strong-named and what does that even mean if signing them didn't help?

EDIT: As requested, the fusionlog entry. I'm not sure what to make of these logs. Seems to me it's looking in the right folders for the assembly, although it seems like it's looking for a signed assembly, where the one I have and have always had is not signed.

=== Pre-bind state information ===
LOG: DisplayName = Word, Version=1.0.0.1, Culture=neutral, PublicKeyToken=null
 (Fully-specified)
LOG: Appbase = file:///<folder>/Word AddIn/bin/Debug/
LOG: Initial PrivatePath = NULL
LOG: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = NULL
Calling assembly : AddIn2013, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null.
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: <folder>\Word AddIn\bin\Debug\AddIn2013.dll.config
LOG: Using host configuration file: 
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///<folder>/Word AddIn/bin/Debug/Word.DLL.
LOG: Assembly download was successful. Attempting setup of file: <folder>\Word AddIn\bin\Debug\Word.dll
LOG: Entering download cache setup phase.
LOG: Assembly Name is: Word, Version=1.0.0.1, Culture=neutral, PublicKeyToken=null
LOG: Binding succeeds. Returns assembly from %appdata%\Local\assembly\dl3\CDT9D6R7.5N1\J6WPRMT3.DDT\48a5090d\952e5901_ee17d201\Word.dll.
LOG: Assembly is loaded in default load context.

EDIT2: To me, it looks like it's looking for a Word.dll and Word.exe somewhere in C:/Program Files (x86)/MSBuild/12.0/bin/ which I am missing.

*** Assembly Binder Log Entry  (27.09.2016 @ 12:56:09) ***

The operation failed.
Bind result: hr = 0x80070002. The system cannot find the file specified.

Assembly manager loaded from:  C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Running under executable  C:\Program Files (x86)\MSBuild\12.0\bin\MSBuild.exe
--- A detailed error log follows. 

=== Pre-bind state information ===
LOG: DisplayName = Word, Version=1.0.0.1, Culture=neutral, PublicKeyToken=null
 (Fully-specified)
LOG: Appbase = file:///C:/Program Files (x86)/MSBuild/12.0/bin/
LOG: Initial PrivatePath = NULL
LOG: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = MSBuild.exe
Calling assembly : (Unknown).
===
LOG: This is an inspection only bind.
LOG: Using application configuration file: C:\Program Files (x86)\MSBuild\12.0\bin\MSBuild.exe.Config
LOG: Using host configuration file: 
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/MSBuild/12.0/bin/Word.DLL.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/MSBuild/12.0/bin/Word/Word.DLL.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/MSBuild/12.0/bin/Word.EXE.
LOG: Attempting download of new URL file:///C:/Program Files (x86)/MSBuild/12.0/bin/Word/Word.EXE.
LOG: All probing URLs attempted and failed.