diff --git a/src/engine/server/server.cpp b/src/engine/server/server.cpp
index fa158b1d4..936c26395 100644
--- a/src/engine/server/server.cpp
+++ b/src/engine/server/server.cpp
@@ -1438,9 +1438,14 @@ int CServer::Run()
 void CServer::ConKick(IConsole::IResult *pResult, void *pUser, int ClientId)
 {
 	int ClientId1 = pResult->GetInteger(0);
-	if (ClientId == -1 || ((CServer *)pUser)->m_aClients[ClientId].m_Authed > ((CServer *)pUser)->m_aClients[ClientId1].m_Authed)
+	char buf[128];
+	if(ClientId1 < 0 || ClientId1 >= MAX_CLIENTS || m_aClients[ClientId1].m_State == CClient::STATE_EMPTY)
+	{
+		str_format(buf, sizeof(buf),"Invalid Client ID %d", ClientId1);
+		((CServer *)pUser)->SendRconLine(ClientId,buf);
+	}
+	else if (ClientId == -1 || ((CServer *)pUser)->m_aClients[ClientId].m_Authed > ((CServer *)pUser)->m_aClients[ClientId1].m_Authed)
 	{
-		char buf[128];
 		str_format(buf, sizeof(buf),"Kicked by %s", ((CServer *)pUser)->ClientName(ClientId));
 		((CServer *)pUser)->Kick(ClientId1, buf);
 	}
diff --git a/src/game/collision.cpp b/src/game/collision.cpp
index fcd937d9b..936fdfafe 100644
--- a/src/game/collision.cpp
+++ b/src/game/collision.cpp
@@ -241,14 +241,14 @@ void CCollision::SetCollisionAt(float x, float y, int flag)
 
 void CCollision::SetDTile(float x, float y, int Team, bool State)
 {
-	if(!m_pDoor || ((Team < 0 || Team > MAX_CLIENTS) && Team !=99))
+	if(!m_pDoor || ((Team < 0 || Team > (MAX_CLIENTS - 1)) && Team !=99))
 		return;
    int nx = clamp(round(x)/32, 0, m_Width-1);
    int ny = clamp(round(y)/32, 0, m_Height-1);
 
 	if(Team == 99)
 	{
-		for (int i = 0; i < MAX_CLIENTS; ++i)
+		for (int i = 0; i < (MAX_CLIENTS - 1); ++i)
 		{
 			m_pDoor[ny * m_Width + nx].m_Team[i] = State;
 		}
@@ -259,7 +259,7 @@ void CCollision::SetDTile(float x, float y, int Team, bool State)
 
 void CCollision::SetDCollisionAt(float x, float y, int Flag, int Team)
 {
-	if(!m_pDoor || ((Team < 0 || Team > MAX_CLIENTS) && Team !=99))
+	if(!m_pDoor || ((Team < 0 || Team > (MAX_CLIENTS - 1)) && Team !=99))
 		return;
    int nx = clamp(round(x)/32, 0, m_Width-1);
    int ny = clamp(round(y)/32, 0, m_Height-1);
@@ -267,7 +267,7 @@ void CCollision::SetDCollisionAt(float x, float y, int Flag, int Team)
    m_pDoor[ny * m_Width + nx].m_Index = Flag;
 	if(Team == 99)
 	{
-		for (int i = 0; i < MAX_CLIENTS; ++i)
+		for (int i = 0; i < (MAX_CLIENTS - 1); ++i)
 		{
 			m_pDoor[ny * m_Width + nx].m_Team[i] = true;
 		}
@@ -278,10 +278,8 @@ void CCollision::SetDCollisionAt(float x, float y, int Flag, int Team)
 
 int CCollision::GetDTileIndex(int Index,int Team)
 {
-	if(!m_pDoor || !m_pDoor[Index].m_Index || ((Team < 0 || Team > MAX_CLIENTS) && Team !=99))
-	{
+	if(!m_pDoor || !m_pDoor[Index].m_Index || ((Team < 0 || Team > (MAX_CLIENTS - 1)) && Team !=99))
 		return 0;
-	}
 
 	if(m_pDoor[Index].m_Team[Team])
 		return m_pDoor[Index].m_Index;