|Possibly driver issue? Or since you mentioned sleep mode... maybe try disabling sleep mode and just do a complete shutdown?|
Try updating your adapters driver?
(e.g. goto trendnets website and download the latest driver)
It could be an ACPI power setting in bio's which is incompatible with your adapter... google ACPI power settings for more information. BTW I never recommend sleep mode to anyone let alone hibernation...