Unable to establish connection to R/3

Hi,

We have just installed XI and done all configurations.

I am doing one example ( connection r/3 to legacy system ) . When I open I outbound object in Integration Repository and in Imported objects when right click on IDocs and click Import SAP Objects, it asks me for SAP logon details , but when I try to connect it shows an error

Unable to establish connection to R/3 system 133.136.233.170 (system=00, client=110) Troubleshooting tips:

Is the target system online?

Check the connection data (note that server names and groups are case-sensitive)

Tips for administrators (see the configuration guide for more details):

Does the user have the required authorizations in the target system?

Is the target system configured correctly in "etc/services"?

I am putting IP address in application server and checked the system number as well.

I am able to ping From webas to R/3.

can anybody help me out what could be the error

Thanks

Rekha