SQL & PL/SQL

Hello,

I am experiencing a problem for which I could not find any references on metalink or the forums.

In my PLSQL program, I am calling the Business Event WF_EVENT api:

wf_event.AddParameterToList(l_key, l_name, l_parameter_list);


Before calling the API above, I declare the variable as follows:

l_parameter_list wf_parameter_list_t := wf_parameter_list_t();

When I run this program, the API invocation gives error: ORA-30625: method dispatch on NULL SELF argument is disallowed

I understand that this error is equivalen of a 'NULL POINTER" exception in the java world.

I can't understand why this exception is being thrown when

1) I have declared and created the variable so it's not null
2) even if it was null, the documentation of wf_event.AddParameterToList says that it creates the list if it is null.

I am quite new to PLSQL, so I am sure I am doing something silly that's causing this problem. Any help you can provide will be much appreciated.

thanks