Is there a place where the Host Settings are defined (possibly document the effect that they have)? 

The issue I am having didn't occur until I upgraded to 4.5.x.  My hosting company (1and1) also has strict policies about their security and stuff. I have managed to get DNN to work, but after the upgrade I get tons of FileIOPermission errors ... I keep having to reset the file system permissions to get it to work.  My thoughts are that I can disable caching and precompiling via the host settings and web.config to get this working.  Essentially, if I can get DNN to run as a fully dynamic data-driven site, without the performance enhancements  ... I think it will just work (which is all I want right now ).  Any feedback is greatly appreciated ... anyone that has dealt with my hoster ... please share any input (and if you have DNN running, please share how I can achive this as well). 

Thanks in advance for your knowledge, opinions and time.

-Brian

I noticed that too but there isn't much to go on there either.  For example, PageStatePersister could mean a lot of things ... but the value it is set to "P" has very little meaning ... and I am hesitant to change it without knowing what are the other possible values.

I presume that all these are configurable via the DNN site, but I can't get that far before I get the FileIO issues.  Hence, I am seeking help and direction before I embark on a code searching quest and such (not that I mind ... I prefer not to reinvent the wheel and also seek guidance from those who are familiar with the code ).  Any help is greatly appreciated.

-Brian

In the HostSettings table, I set PageStatePersister to "M" for memory and  ModuleCaching to "M" for memory as well.  This did exactly what I was looking for, which means mysite is running great.  I am able to login make changes and all FileIO permission errors are gone.  I very much appreciate your help Mitchel, this advice nailed the problem.

A theory as to why I was getting the errors:  My ISP has locked the file system to reduce priviledges to secure all content, such that new files and folders do not inherit the parent folder permissions.  As to how this happens ... could be the account hadling the process, etc ... doesn't really matter because I can't change it and nor will they (useful support eh!).  Needless to say, I managed to install DNN through some effort (and force permissions every time a portal is created).  Any cached files and or temporary files created have the potential of causing IO errors. 

By pushing the caching and such behaviors to memory, my file IO errors are gone ... thus, I am happy.

Thanks again.