In the previous article "Crack C# namespaces in 30 seconds" I demonstrated how to make error having no idea about it. So you will have a lovely time in debugging. But in C# you're condemned to use using directive or your code will be unreadable with all these horrible specifiers MySolution.AppModules.Accounting.AccountingType.DefaultValue.
The namespaces conception in C# seems exhaustive and insufficient at the same time in comparison with strong module notation like in Oberon-2 and even with modular programming like in Free Pascal/Delphi.
Why insufficient? You cannot declare constants and functions within namespaces but you should add a class with constant field or static method for it. It's really sad...
Why exhaustive? The "using" directive with such introduced classes is the source of unexpected errors. Here is an example below.
This bug is reproduced on Delphi 7 and C++Builder 6 at least (probably in later versions too) when starting Borland make utility. Indeed, the message "Fatal: Command arguments too long" and the real problem are as like as chalk and cheese.
Check the length of your PATH variable. In my case the length was > 400 characters. Deleting some paths reduced the length down to 300-350 characters and solve the problem.