Linksys VPN: remote gateway is not responding

I use QuickVPN to connect to the RV042 router in remote location. It worked perfectly for around a year. A few weeks ago, suddenly I can't connect anymore. The error message was 'Remote gateway is not responding'.

I didn't make any changes in both my laptop(Windows XP) and RV042. By the way, PPTP connection was allright. So, what's the problem?

I tried all these things..but it won't solve the problem:
- Turn off the firewall in XP.
- Turn off the firewall in RV042.
- Change MTU size in RV042.
- Add new VPN user.

I tried to install QuickVPN on another computer(same network)..and it didn't work..
I tried to install on a remote computer(XP)..and it works!

So, the problem was definitely on the client side. But I tried to turn off the firewall, anti virus..and still didn't work.

Then suddenly I was thinking about my router..Can it be my router that cause the problem? I opened the router's log and saw this line:
kernel: net/ipv4/netfilter/./broadcom/ip_nat_ipsec.c:ipsec_nat_help Out of table entries
I've no idea what's the meaning of it. But I had a feeling that something's wrong with the router. So, I restarted the router, then tried the QuickVPN..and problem SOLVED..Now QuickVPN is working..