I had the same problem. It seems there is some incompatibility with the latest version of libidobc.2.dylib. You might want to install the bug-fix package iodbc-usr-sdk.zip and give that a try. If this does not work, then I think you will have to reinstall Snow Leopard. I was lucky since Time Machine is backing up my disk and I recovered all the libiodbc.* files that way. Works fine now, though, I've not tested odbc yet.
Another way is to forget the internal web server and install MAMP.