Some of items throw errors in zabbix_server.log file:
14597:20120217:102357.036 [Z3005] query failed: [-1] ORA-01654: unable to extend index ZABBIX.HISTORY_UINT_1 by 8192 in tablespace DATA_TBS
ORA-06512: at line 29 [begin
insert into history (itemid,clock,value,ns) values (51836,1329495836,0.283818,678518000);
insert into history (itemid,clock,value,ns) values (50036,1329495836,6.968750,681375000);
(..)
insert into history_uint (itemid,clock,value,ns) values (50221,1329495836,253,712440000);
insert into history_uint (itemid,clock,value,ns) values (50222,1329495836,245286,712440000);
(..)
insert into history_uint (itemid,clock,value,ns) values (50183,1329495836,1,744430000);
end;
]

There is large number of such errors.