My daily maintenance job fails due to the below error from last 20 days regularly

Executing the query “BACKUP DATABASE [shipment] TO DISK = N’D:\backup\shipment.bak’ WITH NOFORMAT, NOINIT, NAME = N’shipment’, SKIP, REWIND, NOUNLOAD, STATS = 10
” failed with the following error: “Write on “D:\backup\shipment.bak” failed: 112(error not found)
BACKUP DATABASE is terminating abnormally.
10 percent processed.
20 percent processed.
30 percent processed.
40 percent processed.
50 percent processed.”. Possible failure reasons: Problems with the query, “ResultSet” property not set correctly, parameters not set correctly, or connection not established correctly.

very recently i have changed the recovery mode from Full to simple and truncated the log file and i changed back the recovery mode to Full.
Does this affect the db.?

The maintenance plan was set to take the back up of full db.
How to sort this issue.
Sql 2005 on sp2.

Any ideas will help me.

Thanks