I had the same errors on one of my development servers.
As requested, I ran DBCC CHECKDB (<DATABASENAME>) WITH NO_INFOMSGS, ALL_ERRORMSGS.
The errors generated indicated either a replication errror or that the server ran out of space. Upon checking the server for space, I found I had none. I had to attach, then delete some old (useless) databases. I then reran the DBCC CHECKDB. It came back without errors.