I would not be overly concerned about errors in the log unless you are experiencing problems using the site. Lots of errors and info messages will be logged in normal operation in order to make it easier to provide support, but there is usually a lot of noise in the log so when there is a symptom happening that you can re-produce its best to clear the log then cause the symptom and then see what gets logged, otherwise you may interpret the noise as the real problem when it is not.
JIT Debugging failed with the following error: Access is denied. JIT Debugging was initiated by the user account 'TIMPC\ASPNET'.
I'm not sure why thats happening, but thats happening on your local machine not on your hosted site right?
JIT stands for just in time, and its related to the way .NET works. When I compile mojoPortal all the C# code is compiled into CIL aka MSIL (Microsoft Intermediate Language), but when the site gets its first page request, the CIL code is JIT (just in time) compiled to native instructions for the processor and the JIT compiled code get cached into folders beneath Windows\system as you see "File name: 'e:\3e\SYSTEM~1\j2w_jhtt.dll'" in one of your errors. Sometimes things get funky with the caching and you will see errors like this. Restarting the app should clear the cache and the it would normally get JIT compiled again when the app restarts but occassionally I've seen cases where the machine had to be rebooted or there was some other problem interfering with the JIT or caching.
1. Is just logged as INFO, and its normal, every time the application starts we run a task on a background thread to check if there were any unfinished items that need to be indexed into the search index or other tasks that may have been interupted when the application was restarted.
2. Is not an error I've seen and it doesn't give any real clue what caused it but I would not worry about it unless its associated with some problem using the site.
3. Looks like some JIT caching issue, these things can happen from time to time, I would not worry about it unless its causing problems using the site or is happening all the time.
Hope it helps,