--- generic/tclNamesp.c.orig	2008-05-20 15:55:34.983411000 -0400
+++ generic/tclNamesp.c	2008-05-20 15:55:26.504933000 -0400
@@ -6939,6 +6939,10 @@
 	}
     }
 
+    if (length < 0) {
+	length = strlen(command);
+    }
+
     overflow = (length > limit);
     Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
 	    "\n    %s\n\"%.*s%s\"", ((iPtr->errorInfo == NULL)
