[Openswan Users] two tunnel from two clients behind the same IP (NAT Router) won't work, is that right?

[foren titze]

Hello Users,

our two roadwarrrior laptops are behind the same IP in Poland and they can not 
establish a tunnel at the same time to our linux vpn gateway.

I get this errormessage by ipsec:
__________
Apr 12 12:45:50 linux-vpn pluto[7467]: "sse"[12] 62.111.243.xxx:1025 #499: 
sent MR3, ISAKMP SA established
Apr 12 12:45:50 linux-vpn pluto[7467]: "sse"[12] 62.111.243.xxx:1025 #500: 
responding to Quick Mode
Apr 12 12:45:50 linux-vpn pluto[7467]: "sse"[12] 62.111.243.xxx:1025 #500: 
cannot install eroute -- it is in use for "ski"[128] 62.111.243.xxx:4500 #498
___________

I use openswan 1.0.9 with kernel 2.4.28

thanks