Using ConText to index URLs

I am trying to use ConText to create a text index of a list of URLs. I configured the
policy to use URL as the datasource with a timeout of 30 seconds. When I run
ctx._ddl.create_index, however, no index is created and the program gets stuck somewhere, with no error messages. I am forced to Cntl-C it, at which point I get the following message:

ORA-20000: ConText error:
DRG-10302: interrupted waiting for responses from servers
ORA-06512: at "CTXSYS.DRUE", line 180
ORA-06512: at "CTXSYS.CTX_DDL", line 94
ORA-06512: at line 2

                Can someone please give me a hint what's going on.
                Thanks.