I get this exception when I try to generate a nodejs server stub:

I'm surprised that no one else generates nodejs stubs.

My test enviroment:
windows 8.1
jdk8
mvn 3.2.3

I think the problem is in NodeJSServerCodegen.java (line 92):
return outputFolder + File.separator + apiPackage().replaceAll(".", File.separator);
It should be replaced with:
return outputFolder + File.separator + apiPackage().replace('.', File.separatorChar);
This was done in others codegen (ex. JavaClientCodegen.java) but not for the nodejs one.

Searching the code I found other parts that need to be fixed:

C:\Users\Marco\Desktop\swagger\swagger-codegen\modules\swagger-codegen\src\main\java\com\wordnik\swagger\codegen\DefaultGenerator.java 15 KB File JAVA 22/02/2015 08:41:55 22/02/2015 08:41:55 22/02/2015 08:41:55 1
156 bundle.put("apiFolder", config.apiPackage().replaceAll(".", "/"));

C:\Users\Marco\Desktop\swagger\swagger-codegen\modules\swagger-codegen\src\main\java\com\wordnik\swagger\codegen\DefaultCodegen.java 31 KB File JAVA 22/02/2015 08:41:55 22/02/2015 08:41:55 22/02/2015 08:41:55 2
104 return outputFolder + "/" + apiPackage().replaceAll(".", "/");
108 return outputFolder + "/" + modelPackage().replaceAll(".", "/");

C:\Users\Marco\Desktop\swagger\swagger-codegen\modules\swagger-codegen\src\main\java\com\wordnik\swagger\codegen\languages\NodeJSServerCodegen.java 4 KB File JAVA 22/02/2015 10:02:53 22/02/2015 08:41:55 22/02/2015 08:41:55 2
92 return outputFolder + File.separator + apiPackage().replaceAll(".", File.separator);
96 return outputFolder + File.separator + modelPackage().replaceAll(".", File.separator);

C:\Users\Marco\Desktop\swagger\swagger-codegen\modules\swagger-codegen\src\main\java\com\wordnik\swagger\codegen\languages\PythonClientCodegen.java 4 KB File JAVA 22/02/2015 08:41:55 22/02/2015 08:41:55 22/02/2015 08:41:55 2
67 return outputFolder + "/" + apiPackage().replaceAll(".", "/");
71 return outputFolder + "/" + modelPackage().replaceAll(".", "/");

The fix is the same for all:
replace
.replaceAll(".", .... );
with:
.replace('.', File.separatorChar);

Bye.

Marco