You may have tried to load multiple thousands of organisations from one .csv file and you're getting a message that there is a limit of 2,000 organisations per dataload?
The resolve is to "carve up" your file into no more than 2,000 rows (header row? plus 1999 entries max).
With the data on these smaller files you should be ok to load in your organisations within the Business dataload function.
( you can then follow each one with an import of contacts within which you link to organisations)
N.B. make sure for your business dataloads that each company / organisation is only entered ONCE on your file, to avoid creating duplicate organisations.