I tried to use RollingFileAppender in an Web Application. I set the file size limit to 10k and date pattern yyyymmdd.
I was able to create the logfile.txt and when it is over 10k, it can be moved to logfile.txt.1. (This mean there is no access right problem)
However, if I then change the clock of the computer to one day later, RollingFileAppender try to rename logfile.txt to logfile.txt20050721
log4net: RollingFileAppender: Moving [c:\inetpub\wwwroot\virtual\logfile.txt.1] -> [logfile.txt20050721.1]
Obviously the "destination" should be a full path c:\inetpub\wwwroot\virtual\logfile.txt20050721.1
in RollingFileAppender.cs, line 1018 and 1023, call ConvertToFullPath(to) before calling RollFile.