To find out your database's compatibility level, run the following query:
select name, compatibility_level from sys.databases
The number corresponds to the version of SQL Server as shown below:
80 = SQL Server 2000 (or MSDE)
90 = SQL Server 2005
100 = SQL Server 2008
If the compatibility_level value is lower than the version of SQL Server you are using to host the database, you can change the compatibility level to match by using the SQL Server Management Studio software on the server. Right-click on the database name and choose Properties. Then choose the Options page and set the Compatibility Level drop-down option to the highest level available, which will be the same as the version of the SQL Server host.