Have unused space but still couldnt insert records

Hi,
Am using sybase DB.
I have use created objects "TABLE1",

1> sp_spaceused TABLE1
2> go
name rowtotal reserved data index_size unused
---------------------------------- ---------------- ----------------
TABLE1 2587 128 KB 112 KB 0 KB 16 KB

(1 row affected)
(return status = 0)

Was able to insert records upto "2587" rows.But couldn't insert more records even if i have "16KB" as unused space.

In all , I allocated around 35MB to the database in which 8MB was unused and i couldn't insert into any of the tables in the database.


What could be the reason?? What should i do in order to utilize full space allocated(So that unused will be 0KB)???

Thanks.