Secure Share access

[iPod]

Hi,
I love this cool product, and I have recommended it to many people and a few PC Technicians, this is the best VPN ever.
However I do encounter a problem...
I have secure shares which I set up, for a few of our locations. Every other day I am getting bothered that some shares cannot be access with Forbidden HTTP 403 Error.
When I check it on my PC, browse the shares it works fine, nothing was moved.
I then have to re-create the share a few times until it works.
Why is it so? Can it be fixes?
I would really appreciate any help!