Problem loggin into my site

On my localhost, login control works fine.  When I upload to the web server it doesn't work.  This is the message I get:
<!-- Web.Config Configuration File -->

<configuration>
<system.web>
<customErrors mode="RemoteOnly" defaultRedirect="mycustompage.htm"/>
</system.web>
</configuration>
What does it mean?
I went to the web.config file and searched for 'remoteOnly'; I couldn't even find it!
Any ideas about what I need to to do make this work?
Thanks,
Ryan---

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