I think it's better to use the word missing for both error cases.
In the first case the "toolbox.exe wasn't found" which is the same as "toolbox.exe is missing".
I chose the second variant to not use special characters.
Second case is similar to the first one. The current version which is present in the addon manifest is missing in the installer manifest.
The removal of space characters shouldn't change the build file in any sense.
I think it's better to use the word missing for both error cases.
In the first case the "toolbox.exe wasn't found" which is the same as "toolbox.exe is missing". I chose the second variant to not use special characters.
Second case is similar to the first one. The current version which is present in the addon manifest is missing in the installer manifest.
The removal of space characters shouldn't change the build file in any sense.