I have log4j for logging in my struts application.The rolling over is given as midnight.But if i restart my server before it got rolled over and at midnight the rolling over got failed since the same file exists already.
We use log4j at our site http://www.alldiscountbooks.net and I found the similar issue. Not sure, if this problem has been fixed. Thanks.
http://apache-poi.1045710.n5.nabble.com/Apache-POI-Protected-sheet-disables-the-Row-