Access is denied when executing xp_cmdshell delete

[ssshhh]

hi y'all!
here i am again with another problem:

declare @path varchar (100)
declare @filename varchar (100)
delcare @delete_this varchar (100)
declare @cmd varchar (100)

set @path = '"\\servername\ shared\"'
set @filename = 'file.txt'
set @delete_this = @path+@filename
set @cmd = 'del '+@delete_this

exec master..xp_cmds hell @cmd

i get this:

Access is denied.

Please Advise
Thnx.

[ssshhh]

I've also heard of "net use"

Can u please enlighten me on this.