I had a running openSUSE 10.3 system with ZABBIX 1.6.5 and trouble-free IPMI-items.
Now I've changed to openSUSE 11.1 and the IPMI-items are out of order. I have the same OpenIPMI-Version 2.0.14 running as on the previous OS.

Here are some debuglog-outputs of ZABBIX:
I think the main problem is the entry: "Cannot connect to IPMI host. Error 0x16 Invalid argument"
But a query to the IPMI-card with ipmitool is working properly.

26215:20090809:030057 In setup_done() [192.168.1.1]:623
26215:20090809:030057 In domain_closed() [192.168.1.1]:623
26215:20090809:030057 Cannot connect to IPMI host. Error 0x16 Invalid argument
26215:20090809:030057 End get_value()
26215:20090809:030057 Query [begin;]
26215:20090809:030057 Host [ipmihost]: first network error, wait for 15 seconds
26215:20090809:030057 In zabbix_log()
26215:20090809:030057 Query [select i.itemid,i.key_,h.host,h.port,i.delay,i.description,i.nextcheck,i.type,i.snmp_community,i.snmp_oid,h.useip,h.ip,i.history,i.lastvalue,i.prevvalue,i.hostid,h.status,i.value_type,h.errors_from,i.snmp_port,i.delta,i.prevorgvalue,i.lastclock,i.units,i.multiplier,i.snmpv3_securityname,i.snmpv3_securitylevel,i.snmpv3_authpassphrase,i.snmpv3_privpassphrase,i.formula,h.available,i.status,i.trapper_hosts,i.logtimefmt,i.valuemapid,i.delay_flex,h.dns,i.params,i.trends,h.useipmi,h.ipmi_port,h.ipmi_authtype,h.ipmi_privilege,h.ipmi_username,h.ipmi_password,i.ipmi_sensor,i.lastlogsize from hosts h, items i where h.hostid=i.hostid and h.status=0 and i.status=0 and h.proxy_hostid=0 and i.key_='zabbix[log]' and i.value_type=1 and h.hostid between 000000000000000 and 099999999999999]
26215:20090809:030057 Query [update hosts set errors_from=1249779657,disable_until=1249779672 where hostid=10022]
26215:20090809:030057 Parameter [cpu2_temp] will be checked after 120 seconds on host [ipmihost]
26215:20090809:030057 Query [update items set nextcheck=1249779777 where itemid=41999]
26215:20090809:030057 Query [commit;]
26215:20090809:030057 In substitute_simple_macros (data:"192.168.1.1")
26215:20090809:030057 In int_in_list(list:10022,value:10022)
26215:20090809:030057 End int_in_list(ret:SUCCEED)
26215:20090809:030057 Host 10022 is unreachable. Skipping [cpu3_temp]
26215:20090809:030057 In substitute_simple_macros (data:"192.168.1.1")
26215:20090809:030057 In int_in_list(list:10022,value:10022)
26215:20090809:030057 End int_in_list(ret:SUCCEED)
26215:20090809:030057 Host 10022 is unreachable. Skipping [cpu4_temp]
26215:20090809:030057 In substitute_simple_macros (data:"192.168.1.1")
26215:20090809:030057 In int_in_list(list:10022,value:10022)
26215:20090809:030057 End int_in_list(ret:SUCCEED)