Fixed MString and MFile.

ZString.cpp

@@ -117,11 +117,18 @@ namespace coreutils {
    }
 
    bool ZString::operator!=(const char *valuex) const {
-      if(strlen(valuex) != length)
-        return true;
-      return (strncmp(data, valuex, length) != 0);
+      if(valuex == NULL) {
+	 if(length == 0)
+	   return false;
+	 else
+	   return true;
+      } else {	   
+	 if(strlen(valuex) != length)
+	   return true;
+	 return (strncmp(data, valuex, length) != 0);
+      }
    }
-
+   
    std::vector<ZString> &ZString::getList() {
       return list;
    }