os 10.6.8 alias linking to another file

so I have some aliasis on my desktop and everyonce and a while they loose the direction and link to another file. the link is on my desktop and goes to my drobo it works but it sometimes links to another file alltogether. even if the issue is the drobo (server) the alias that is on my desktop should then default to file not found not linking to another files? so I am worried that maybe my desktop is at fault. namely my home directory.. thanks for all the help in advance