This problem still excists and no cause can be found.
I Entered this on the Microsoft Helpdesk (we've got platinum support) but they cannot solve this either.
Recentley we where supported by a microsoft engineer for a project and aksed him if he was familiar with this problem but he also was scratching his head again and again.
As mentioned in the opening text this is still a random issue which occurs every now and then. The Timeout could be related to several parts on the hardware and/or probably to some software as well. . . . .
No sollution yet !!
Hope this will be sollved when we move over to MS Windows 2008 (running SQL Server 2008) within several months.
I can give you one small hint though;
examin your HBA's queue depth length and set it at least to 128.
We're hosting our SAN and they once set this queue depth length to 4 . . . .
by upgrading this setting we encounter a 8x speed up of our most heavly used systems and probably lose the semaphore issue. . .(I hope)