the page loads immediately and I am also using the shub in modem mode. When it is modem mode the shub doesn't do anything at all, especially populate routing tables. What your routing table is basically doing is saying that anything and everything needs to head out to 81.109.124.1 (the ip address of your outside VM cmts to which you are connected) and then from there it will route your traffic accordingly. The problem you have got is that you are getting it out to the cmts, it is after that that there is a problem. The interesting thing is that even though you say it works fine in router mode, it is in router mode that your trace route fails.
C:\Users\General Maximus>tracert
www.barco.com
Tracing route to
www.barco.com [81.247.254.134]
over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms CORE-ROUTER [18.19.1.1]
2 * * * Request timed out.
3 11 ms 11 ms 12 ms nott-core-2b-xe-1132-0.network.virginmedia.net [62.255.231.69]
4 * * * Request timed out.
5 * * * Request timed out.
6 14 ms 15 ms 14 ms popl-bb-1b-ae0-0.network.virginmedia.net [62.254.42.90]
7 17 ms 15 ms 16 ms m674-mp2.cvx1-b.lis.dial.ntli.net [62.254.42.162]
8 16 ms 16 ms 14 ms ix-7-0.tcore2.LDN-London.as6453.net [80.231.62.5]
9 37 ms 28 ms 29 ms if-26-2.tcore1.LDN-London.as6453.net [80.231.62.58]
10 27 ms 32 ms 26 ms if-17-2.tcore1.L78-London.as6453.net [80.231.130.129]
11 29 ms 28 ms 27 ms if-3-6.tcore1.PYE-Paris.as6453.net [80.231.130.86]
12 29 ms 31 ms 29 ms if-2-2.tcore1.PVU-Paris.as6453.net [80.231.154.17]
13 27 ms 28 ms 31 ms if-32-2.thar1.B1D-Brussels.as6453.net [195.219.241.10]
14 * * * Request timed out.
15 34 ms 37 ms 37 ms lag-26-1000.iprmar1.isp.belgacom.be [91.183.246.140]
16 42 ms 39 ms 35 ms 173.246-183-91.adsl-static.isp.belgacom.be [91.183.246.173]
17 37 ms 35 ms 36 ms 213.181.52.1
18 * * * Request timed out.
19 * * * Request timed out.
20 * * * Request timed out.
21 * * * Request timed out.
22 * * * Request timed out.
23 * * * Request timed out.
24 * * * Request timed out.
25 * * * Request timed out.
26 * * * Request timed out.
27 * * * Request timed out.
28 * * * Request timed out.
29 * * * Request timed out.
30 * * * Request timed out.
Trace complete.