Merge statement not working over db link

Question

I have a merge statement that works fine when it's run against a local table, but when I try to run it against a table over a database link, I get the following error.
ERROR at line 1:
ORA-01008: not all variables bound
ORA-02063: preceding line from REPOS
ORA-06512: at "DBADMIN.PING_DB", line 6
ORA-06512: at line 1
Here is the code:
create or replace procedure ping_db
as
begin
merge into availability@repos A
using (select trunc(sysdate) from dual)
on (trunc(A.day) = trunc(sysdate))
when matched then update set A.uptime = A.uptime + 1
when not matched then insert (hostname,dbname,day,uptime) values
(utl_inaddr.get_host_name,sys.database_name,trunc(sysdate),1);
commit;
end;
/Code compiles fine, but gets the error when it's executed. Any help would be appreciated.

Answer 1

9.2.0.x is the version (9.2.0.4,.5 and .6)