diff --git a/engine/client/pr_csqc.c b/engine/client/pr_csqc.c
index 615908ffe..4a13ea1b8 100644
--- a/engine/client/pr_csqc.c
+++ b/engine/client/pr_csqc.c
@@ -5025,7 +5025,10 @@ void CSQC_Event_Think(world_t *w, wedict_t *s)
 	*csqcg.other = EDICT_TO_PROG(w->progs, (edict_t*)w->edicts);
 	*csqcg.simtime = w->physicstime;
 
-	PR_ExecuteProgram (w->progs, s->v->think);
+	if (!s->v->think)
+		Con_Printf("CSQC entity \"%s\" has nextthink with no think function\n", PR_GetString(w->progs, s->v->classname));
+	else
+		PR_ExecuteProgram (w->progs, s->v->think);
 }
 
 void CSQC_Event_Sound (float *origin, wedict_t *wentity, int channel, char *sample, int volume, float attenuation, int pitchadj)
diff --git a/engine/qclib/pr_exec.c b/engine/qclib/pr_exec.c
index a2a9eeedc..c5c9bfcef 100644
--- a/engine/qclib/pr_exec.c
+++ b/engine/qclib/pr_exec.c
@@ -1365,7 +1365,11 @@ void PDECL PR_ExecuteProgram (pubprogfuncs_t *ppf, func_t fnum)
 	{
 //		if (pr_global_struct->self)
 //			ED_Print (PROG_TO_EDICT(pr_global_struct->self));
+#ifdef __GNUC__
+		printf("PR_ExecuteProgram: NULL function from exe (address %p)\n", __builtin_return_address(0));
+#else
 		printf("PR_ExecuteProgram: NULL function from exe\n");
+#endif
 //		Host_Error ("PR_ExecuteProgram: NULL function from exe");
 
 //		PR_MoveParms(0, pr_typecurrent);
diff --git a/engine/server/pr_cmds.c b/engine/server/pr_cmds.c
index 01c4ca318..94707448e 100644
--- a/engine/server/pr_cmds.c
+++ b/engine/server/pr_cmds.c
@@ -533,7 +533,10 @@ void SVPR_Event_Think(world_t *w, wedict_t *s)
 {
 	pr_global_struct->self = EDICT_TO_PROG(w->progs, s);
 	pr_global_struct->other = EDICT_TO_PROG(w->progs, w->edicts);
-	PR_ExecuteProgram (w->progs, s->v->think);
+	if (!s->v->think)
+		Con_Printf("SSQC entity \"%s\" has nextthink with no think function\n", PR_GetString(w->progs, s->v->classname));
+	else
+		PR_ExecuteProgram (w->progs, s->v->think);
 }
 
 qboolean SVPR_Event_ContentsTransition(world_t *w, wedict_t *ent, int oldwatertype, int newwatertype)
diff --git a/engine/server/sv_user.c b/engine/server/sv_user.c
index 52b30d401..6c6cbda28 100644
--- a/engine/server/sv_user.c
+++ b/engine/server/sv_user.c
@@ -1716,7 +1716,7 @@ void SV_Begin_Core(client_t *split)
 			{
 				eval_t *eval, *eval2;
 				eval = PR_FindGlobal(svprogfuncs, "ClientReEnter", 0, NULL);
-				if (eval && split->spawninfo)
+				if (eval && eval->function && split->spawninfo)
 				{
 					globalvars_t *pr_globals = PR_globals(svprogfuncs, PR_CURRENT);
 					int j;