I used the advice below to solve this issue
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It most definetly is because of lack of rights. The ASPNET user on your
machine probably runs as userName="machine" (look for processmodel in
machine.config), which means that it is kept from harming your system.
The easy way to solve this is by setting this attribute to
userName="system". However by doing this the ASPNET user suddenly becomes
god on your machine and makes it vulnerable. Unfortunately I do not know of
a way to give the ASPNET user just enough right to create an event source,
and you're right about the info on the .NET. Everyone takes the easy way and
sets username="system".
Anyway, you can write til the "Application" event log by setting
logname="Application".