i had the same problem, and i posted a thread asking for help.... i got some good answers.... i dont know how to quote the link to the thread i started (i am kinda of new at this).... but i started leaving Chloe in a confine space while i WAS home, and disappear for short periods of time.... then letting her see me... then increase my "Away" time and she has been getting used to it.. also i always leave the TV (on Animal Planet
cuz she loves it) or a radio on for her to hear voices while i am away.... it worked for me... and she's behaving pretty good lately... she always whines a little when i first put her in the play pen, but she calms down almost immediately....
maybe try that....good luck!