There have been two versions of SoD on Steam. If you look in your EQ folder, in the logs\dbg.txt file, on the first line:
If it says:
Code:
(Built Dec 19 2008 15:22:49)
Then this is the first version that was available and works very well.
If it says:
Code:
(Built Jun 8 2010 16:44:32)
Then this is an updated version, that is sometimes referred to as the 'Underfoot' client. Servers that haven't updated their code in a couple of months may not support this version. The code support is not so good for this version and may be the cause of the bugs you are seeing.
People who downloaded the 'original' version of SoD from Steam and who didn't copy the game elsewhere, or disable Steam from automatically updating it will also have been upgraded to the 'Underfoot' version.