Server compilation on ubuntu 8.10 ended up with that error.

[4 of 4] Compiling Main             ( /home/jurek/Pulpit/Hedgewars/netserver/hedgewars-server.hs, /home/jurek/Pulpit/Hedgewars/netserver/Main.o )

/home/jurek/Pulpit/Hedgewars/netserver/hedgewars-server.hs:43:29:
    Illegal signature in pattern: IOException
        Use -XPatternSignatures to permit it

/home/jurek/Pulpit/Hedgewars/netserver/hedgewars-server.hs:80:5:
    Illegal signature in pattern: IOException
        Use -XPatternSignatures to permit it

/home/jurek/Pulpit/Hedgewars/netserver/hedgewars-server.hs:87:30:
    Illegal signature in pattern: IOException
        Use -XPatternSignatures to permit it
make[2]: *** [bin/hedgewars-server] Błąd 1
make[1]: *** [netserver/CMakeFiles/hedgewars-server.dir/all] Błąd 2
make: *** [all] Błąd 2

The temporary solution is to edit CMakeLists.txt in netserver folder and add this line:
-XPatternSignatures
below line 21

Later you must change all IOExeption's in file hedgewars-server.hs in lines 43,80 and 87 change to Exeption's

With that changes you can compile it but i dunno how it will work. On localhost it works well ;P