diff --git a/projects/mtg/src/MTGDeck.cpp b/projects/mtg/src/MTGDeck.cpp
index f29e31b9c..2b7f55505 100644
--- a/projects/mtg/src/MTGDeck.cpp
+++ b/projects/mtg/src/MTGDeck.cpp
@@ -19,7 +19,7 @@ int MTGAllCards::processConfLine(string s, MTGCard *card){
 #if defined (_DEBUG)
     if (s.size() && s[0] == '#') return 0;
     char buffer[4096];
-    sprintf(buffer, "MTGDECK: Bad Line in %s/_cards.dat:\n    %s\n", setlist[card->setId], s.c_str());
+    sprintf(buffer, "MTGDECK: Bad Line in %s/_cards.dat:\n    %s\n", setlist[card->setId].c_str(), s.c_str());
     OutputDebugString(buffer);
 #endif
     return 0;