vacuum messages

I'm getting the following output from a vacuum:

NOTICE: Index reports_pkey: NUMBER OF INDEX' TUPLES (26280) IS NOT THE
SAME AS HEAP' (26279)
NOTICE: Index reports_pkey: NUMBER OF INDEX' TUPLES (26280) IS NOT THE
SAME AS HEAP' (26279)

I read somewhere on the Internet that the best way to fix this is to
drop the index and recreate it. Not having much experience with
databases,
I'm afraid to do this for fear of screwing up the db. The index was
created automatically when I created the table so I'm not sure of the
proper way to recreate it. Can someone provide me with details of how
to do this properly? Will it do any harm to leave it as is? If it helps,
here is the definition of the index:

discrepancy=> \d reports_pkey
Table = reports_pkey
+----------------------------------+----------------------------------+-------+
| Field | Type |
Length|
+----------------------------------+----------------------------------+-------+
| tracking_num | int4
| 4 |
+----------------------------------+----------------------------------+-------+

Thanks,
David