diff --git a/PacketLib.xcodeproj/project.xcworkspace/xcuserdata/bulgarelli.xcuserdatad/UserInterfaceState.xcuserstate b/PacketLib.xcodeproj/project.xcworkspace/xcuserdata/bulgarelli.xcuserdatad/UserInterfaceState.xcuserstate
index bd293efd0c44e66f9fdc8a0f1a31eb8b6316d253..1db0c31aaa7dc20c73b3174ed4d2c5b28d8e3f61 100644
Binary files a/PacketLib.xcodeproj/project.xcworkspace/xcuserdata/bulgarelli.xcuserdatad/UserInterfaceState.xcuserstate and b/PacketLib.xcodeproj/project.xcworkspace/xcuserdata/bulgarelli.xcuserdatad/UserInterfaceState.xcuserstate differ
diff --git a/src/PacketStream.cpp b/src/PacketStream.cpp
index 1d8072d9ccbb8f5d21887aa41e517cf326f82a67..c45ffc01cc0d2395f95644cea142a16a4076931f 100644
--- a/src/PacketStream.cpp
+++ b/src/PacketStream.cpp
@@ -200,7 +200,10 @@ bool PacketStream::createStreamStructure() throw(PacketException*)
                 /// dimensione of prefix
                 //delete[] line;
                 line = config.getLine();
-                dimPrefix = atoi(line);
+				if(prefix == false)
+					dimPrefix = 0;
+				else
+					dimPrefix = atoi(line);
             }
             else
                 throw new PacketExceptionFileFormat("No [Configuration] section found.");