After upgrading from 1.6.4 to 1.8 some of my database checks fails with following error:
24677:20100106:121519.358 Failed to connect to DSN '' : Error: failed connection [[unixODBC][Driver Manager]Can't initiate unicode conversion] (0)
24677:20100106:121519.358 Item [edocsp2.uk.db.com:db.odbc.select[e-DOCS Database Invalid Objects count]] error: failed connection [[unixODBC][Driver Manager]
Can't initiate unicode conversion] (0)
24677:20100106:121519.358 In zabbix_log()
24677:20100106:121519.358 In DCconfig_get_items() hostid:0 key:'zabbix[log]'
24677:20100106:121519.358 End of DCconfig_get_items():0
24677:20100106:121519.358 End of zabbix_log()
24677:20100106:121519.358 End of get_value():NOTSUPPORTED
24677:20100106:121519.358 Parameter [edocsp2.uk.db.com:db.odbc.select[e-DOCS Database Invalid Objects count]] is not supported by agent Old status [0]

Further investigations showed that this error occurs when empty DSN, User and Pass parameters were passed to odbc_DBconnect procedure.

All parameters in front end are set correctly and nothing was changed since it was working in Z 1.6.4.

I tried to re-enable the item, but the next time it fails as well.

edocsp2.uk.db.com:db.odbc.select[e-DOCS Database Invalid Objects count] set as below:

DSN=EDOCS
user=user
password=password
sql=select count from user_objects where status <> 'VALID'

(not as DSN=EDOCS\nuser=user\npassword=password\nsql=select count from user_objects where status <> 'VALID' )