Problems when using aspnet_compiler.exe

[Guest]

When compiling my web site with Visual Studio everything works fine. But when
bulding on our build server using the aspnet compiler (aspnet_compiler.exe),
I get the message "error ASPPARSE: Could not load type <namespace>.<class>".

I call aspnet_compiler from a nant script:

aspnet_compiler -nologo -v <virtual path> -p <physical path> -u -f <target
path>

The type that cannot be loaded belongs to a user control located in a sub
directory of the web application. Both the aspx- and cs-files are there.

Any ideas why this doesn't work?