It's probably a typo. Look for the places in your code where you call [schema].[TableName] (basically anywhere you reference a field) and make sure everything is spelled correctly.
Personally, I try to avoid this by using aliases for all my tables. It helps tremendously when you can shorten a long table name to an acronym of it's description (i.e. WorkOrderParts -> WOP), and also makes your query more readable.
Edit: As an added bonus, you'll save TONS of keystrokes when all you have to type is a three or four-letter alias vs. the schema, table, and field names all together.