Not sure what can be of interest here but include some lines from
/var/log/zabbix/zabbix_server.log
14046:20080428:035620 Expression [{13997}>100] cannot be evaluated [Unable to get value for functionid [13997]]
14047:20080428:035622 Expression [{13999}>100] cannot be evaluated [Unable to get value for functionid [13999]]
14048:20080428:035622 Expression [{14001}>0] cannot be evaluated [Unable to get value for functionid [14001]]
14053:20080428:035622 Expression [{14365}>0] cannot be evaluated [Unable to get value for functionid [14365]]
14055:20080428:035624 Expression [{14369}>0] cannot be evaluated [Unable to get value for functionid [14369]]
14049:20080428:035624 Expression [{14003}>100] cannot be evaluated [Unable to get value for functionid [14003]]
14050:20080428:035624 Expression [{14414}>100] cannot be evaluated [Unable to get value for functionid [14414]]
14056:20080428:035625 Expression [{14371}>150000] cannot be evaluated [Unable to get value for functionid [14371]]
14057:20080428:035626 Expression [{14373}>0] cannot be evaluated [Unable to get value for functionid [14373]]
14051:20080428:035626 Expression [{14007}>0] cannot be evaluated [Unable to get value for functionid [14007]]
14052:20080428:035626 Expression [{14009}>150000] cannot be evaluated [Unable to get value for functionid [14009]]
14058:20080428:035627 Expression [{14375}>150000] cannot be evaluated [Unable to get value for functionid [14375]]
14059:20080428:035628 Expression [{14377}>0] cannot be evaluated [Unable to get value for functionid [14377]]
14053:20080428:035628 Expression [{14011}>0] cannot be evaluated [Unable to get value for functionid [14011]]
14049:20080428:035628 Expression [{14253}>150000] cannot be evaluated [Unable to get value for functionid [14253]]
14060:20080428:035629 Expression [{14379}>150000] cannot be evaluated [Unable to get value for functionid [14379]]
14042:20080428:035629 One child process died. Exiting ...
/etc/zabbix/externalscripts/icmp_ping: line 8: echo: write error: Broken pipe
/etc/zabbix/externalscripts/icmp_ping: line 8: echo: write error: Broken pipe
14042:20080428:035631 ZABBIX Server stopped
/etc/zabbix/externalscripts/icmp_ping: line 5: echo: write error: Broken pipe
/etc/zabbix/externalscripts/icmp_ping: line 5: echo: write error: Broken pipe
/etc/zabbix/externalscripts/icmp_ping: line 5: echo: write error: Broken pipe
/var/log/zabbix/zabbix_server.log
14046:20080428:035620 Expression [{13997}>100] cannot be evaluated [Unable to get value for functionid [13997]]
14047:20080428:035622 Expression [{13999}>100] cannot be evaluated [Unable to get value for functionid [13999]]
14048:20080428:035622 Expression [{14001}>0] cannot be evaluated [Unable to get value for functionid [14001]]
14053:20080428:035622 Expression [{14365}>0] cannot be evaluated [Unable to get value for functionid [14365]]
14055:20080428:035624 Expression [{14369}>0] cannot be evaluated [Unable to get value for functionid [14369]]
14049:20080428:035624 Expression [{14003}>100] cannot be evaluated [Unable to get value for functionid [14003]]
14050:20080428:035624 Expression [{14414}>100] cannot be evaluated [Unable to get value for functionid [14414]]
14056:20080428:035625 Expression [{14371}>150000] cannot be evaluated [Unable to get value for functionid [14371]]
14057:20080428:035626 Expression [{14373}>0] cannot be evaluated [Unable to get value for functionid [14373]]
14051:20080428:035626 Expression [{14007}>0] cannot be evaluated [Unable to get value for functionid [14007]]
14052:20080428:035626 Expression [{14009}>150000] cannot be evaluated [Unable to get value for functionid [14009]]
14058:20080428:035627 Expression [{14375}>150000] cannot be evaluated [Unable to get value for functionid [14375]]
14059:20080428:035628 Expression [{14377}>0] cannot be evaluated [Unable to get value for functionid [14377]]
14053:20080428:035628 Expression [{14011}>0] cannot be evaluated [Unable to get value for functionid [14011]]
14049:20080428:035628 Expression [{14253}>150000] cannot be evaluated [Unable to get value for functionid [14253]]
14060:20080428:035629 Expression [{14379}>150000] cannot be evaluated [Unable to get value for functionid [14379]]
14042:20080428:035629 One child process died. Exiting ...
/etc/zabbix/externalscripts/icmp_ping: line 8: echo: write error: Broken pipe
/etc/zabbix/externalscripts/icmp_ping: line 8: echo: write error: Broken pipe
14042:20080428:035631 ZABBIX Server stopped
/etc/zabbix/externalscripts/icmp_ping: line 5: echo: write error: Broken pipe
/etc/zabbix/externalscripts/icmp_ping: line 5: echo: write error: Broken pipe
/etc/zabbix/externalscripts/icmp_ping: line 5: echo: write error: Broken pipe