Roles are not Migrating

Hi,

I am unable to migrate the roles from R/3 system to portal by using Role Upload tool.

I am getting the below error:

<b>"Could not perform action. Check the role migration log for additional information"</b>

And in log file it showing:

Connection Failed: Nested Exception. Native connection to the back end system is broken.

     at com.sap.portal.pcd.rolemigration.util.Connector.callFunction(Connector.java:244)

     at com.sap.portal.pcd.rolemigration.RoleMigration.getImportList(RoleMigration.java:864)

     at com.sap.portal.pcd.admintools.roleMigration.MigrationHandling.getSearchList(MigrationHandling.java:75)

     at com.sap.portal.pcd.admintools.roleMigration.pages.Page1.doSearch(Page1.java:870)

     at com.sap.portal.pcd.admintools.roleMigration.pages.Page1.dispatchPageRequest(Page1.java:680)

     at com.sap.portal.pcd.admintools.roleMigration.DefaultMain.doContent(DefaultMain.java:52)

Can anyone give me solution in solving the migration problem.

thanks in advance,

Sathish.