diff --git a/source/core/r_data/gldefs.cpp b/source/core/r_data/gldefs.cpp
index 0424688ab..c8b4534e8 100644
--- a/source/core/r_data/gldefs.cpp
+++ b/source/core/r_data/gldefs.cpp
@@ -1558,7 +1558,7 @@ class GLDefsParser
 						if (!(cvar->GetFlags() & CVAR_MOD))
 						{
 							if (!((cvar->GetFlags() & (CVAR_AUTO | CVAR_UNSETTABLE)) == (CVAR_AUTO | CVAR_UNSETTABLE)))
-								sc.ScriptError("CVAR '%s' already in use!", cvarname);
+								sc.ScriptError("CVAR '%s' already in use!", cvarname.GetChars());
 						}
 						
 						UCVarValue val;