error: A1355U: A Label was found which was in no AREA

I have the source code follows:

ROM_LOAD 0x00000000
{
    ROM_EXEC 0x00000000
    {
        Startup.o (vectors, +First)
        * (+RO)
    }

    IRAM 0x40000000
    {
        Startup.o (MyStacks)
        * (+RW,+ZI)
    }

    HEAP_BOTTOM +0 UNINIT
    {
        Startup.o (HeapBottom)
    }

    STACKS_BOTTOM +0 UNINIT
    {
        Startup.o (StackBottom)
    }

    STACKS 0x40001000 UNINIT
    {
         Startup.o (HeapTop)
         Startup.o (StacksTop)
    }
}

I have the source code follows:

ROM_LOAD 0x00000000
{
    ROM_EXEC 0x00000000
    {
        Startup.o (vectors, +First)
        * (+RO)
    }

    IRAM 0x40000000
    {
        Startup.o (MyStacks)
        * (+RW,+ZI)
    }

    HEAP_BOTTOM +0 UNINIT
    {
        Startup.o (HeapBottom)
    }

    STACKS_BOTTOM +0 UNINIT
    {
        Startup.o (StackBottom)
    }

    STACKS 0x40001000 UNINIT
    {
         Startup.o (HeapTop)
         Startup.o (StacksTop)
    }
}