Could not write to debug.log

Ok try following

start camelot.exe as administrator one time, then exit
then
start phoenix.exe as administrator

I found another solution in dolserver forum at the following URL
http://support.darkageofcamelot.com/kb/article.php?id=952:

I receive a message with the error ‘cannot write to debug.log’ and then the game crashes.
To resolve this, please delete your log files. You can find them in your My Documents folder under the Electronic Arts/Dark Age of Camelot subdirectory. Be sure to remove the following files:

animnode.log
debug.log
critical.log
ui.log
world.log

Once the files are deleted, please try logging into the game. The error message should be resolved.