Scripting question

["Anil Gupte" <anil-list@icinema.com>]

Why does

echo /l3dat/${Serial_Nuumber}.tar.gz

give me

/l3dat/ TLO00003.tar.gz

In other words, why is it putting an etra space in there (after the second /) 
and how can I get rid of it?

And yes, there is no space there.  I checked by using

Serial_Number=${Serial_Number##" "}

and the variable prints the same before and after.

Thanx in advance for any help.
Anil Gupte