Function geomunion() problem

[santy]

Hi,

Here is the URL for my application http://www.wetlandsofindia.org/kerala/sample.htm
When I search as below

District: Palakkad
Then select Panchayat option
Bloack: Ottappalam

Then hit Submit.

It shows me the boundary of Ottappalam block but it shows me a line
joining the polygon.

I am using following query to return the boundary

select btrim(astext(transform(geomunion(geometry), 4326)),'MULTIPOLYGON
()') from k_panchayat where
district like '%$district%' and block like '%$block%' group by block

It returns me a single polygon only but somehow I do not understand
from where the line is coming.

I am looking for the solution.

Thanks

Santosh