You're almost there. Use the following regex (with multi-line option enabled)
\bObject Name:\s+(.*)$
The complete match would be
Object Name: D:\ApacheTomcat\apache-tomcat-6.0.36\logs\localhost.2013-07-01.log
while the captured group one would contain
D:\ApacheTomcat\apache-tomcat-6.0.36\logs\localhost.2013-07-01.log
If you want to capture the file path directly use
(?m)(?<=\bObject Name:).*$