CVS ml-pnet doesn't build

Fails with the latest SVN or release of mono:

Making all in Custommarshalers
make[2]: Entering directory 
`/home/jhc/dotgnu/ml-pnet/class/Custommarshalers'
"/usr/bin/csant" --compiler cscc -Dcscc="/usr/bin/cscc" 
-Dcscc.plugins.cs="/usr/lib/cscc/plugins/cscc-cs" --profile 
"../../profiles/framework1.1" -Ddebug.flag="true" 
-Dilgac="/usr/bin/ilgac" --assembly-cache "/usr/lib/cscc/lib" 
-DFRAMEWORK_VERSION="2.0.3600.0" -DSECONDARY_VERSION="8.0.1200.0" 
-Dmono.sources="/home/jhc/dotgnu/ml-pnet/../mono/mcs" \
		-b "." -B . -f Custommarshalers.build all
/home/jhc/dotgnu/ml-pnet/../mono/mcs/class/Custommarshalers/Assembly/AssemblyInfo.cs:36: 
invalid type specification `(null)'
/home/jhc/dotgnu/ml-pnet/../mono/mcs/class/Custommarshalers/Assembly/AssemblyInfo.cs:36: 
`int' does not inherit from `System.Attribute'

Totally new to C#, so I have no idea.