Weird trouble with select

Hi!

I have 3 pc's:
pc 'A' with postgres 7.2 running
pc 'B' and 'C' connected to 'A'

if i made the next query on 'B' or 'C' : "select * from detail with
id=72"; takes too long time to return the data, near of 10 minutes
more or less.
if i made the next query on 'B' or 'C' : "select * from detail with
id=71", or whatever value in id , the data are returned immediatly.

if i made the next query on 'A' (postgres server): "select * from
detail with id=72", the data are returned immediatly.

i tried to recreate de database ( drop and create), but i got the same
result on 'B' and 'C' pc's.

But when i made the query on another scenary ( 'D' and 'E' with 'F'
like postgres server) with the same database the works fine.

So i am intrigued, i checked the network connection but looks fine,
if you can help me with this, i will thankfull with you!

Regards, e-ddie.