Eeep. That does not look good.
There's no way that I know of to get a negative page number, as the page number is an incremental count of 8k chunks of the data file.
Can you run a checkDB on that database? If possible, before you restart the service.
DBCC CHECKDB (< Database Name > ) WITH NO_INFOMSGS, ALL_ERRORMSGS
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability