Object guid hast an Negative Value

[Robske]

Take a look at how WoW does it

.text:00659190                 push    ebp
.text:00659191                 mov     ebp, esp
.text:00659193                 sub     esp, 14h
.text:00659196                 push    esi
.text:00659197                 mov     esi, ecx
.text:00659199                 cmp     dword ptr [esi+4], 0
.text:0065919D                 jz      short loc_6591B9
.text:0065919F                 call    sub_84F310
.text:006591A4                 push    eax
.text:006591A5                 push    offset aHasLostTheGame; "%s has lost the game"...
.text:006591AA                 call    nullsub_5
.text:006591AF                 add     esp, 8
.text:006591B2                 pop     esi
.text:006591B3                 mov     esp, ebp
.text:006591B5                 pop     ebp
.text:006591B6                 retn    8

It's from an older client (1.3, subversion 3.7) so you'll have to update your proxies

Edit: Apoc beat me on the proxies by milliseconds!