lol
first of all 127x127x32 map?
that doesnt work
you need a 128x128x32 i think
and 511x64x511 doesnt works too
you will need 512x64x512 to get it work
that error you get is probaly something with this

hope it fixes this
oh and this are the allowed numbers
16 32 64 128 256 512 and 1024
when you do a higher number your computer probaly cant handle it
also smaller then 16 is impossible too
funny thing: you did 511 and 127 haha thats exactly 1 less then it must be =P you where close

I'm having the same problem, I need a map size at roughly 2048 x 2048 x 2048 To build the Imperial City from Oblivion, but every time I try to load the map my browser crashes (however the server appears to run it fine.)

You must type /newlvl <name> 128 64 128 and then some of this  names of types like Flat

There is:
Flat

An otherwise standard design which is not randomly generated, but is
instead simply a vast grassy plain. These are usually created by various
external generators.

Ocean

Ocean maps usually consist of mostly or entirely water to encourage
building underwater structures; they may also be dry at first, but
flooded later, after players have built on them. These gained more
prominence when sponges were added.

Cave

A server which is mostly or entirely an elaborate cave or series of
caves, far more spacious and dynamic than standard caves. These commonly
have the top and sides blocked off with admincrete to stop light getting through.

Landscape

Landscape server with widely varying features across the map, such as
caves, forests, mountains and oceans. These are commonly custom-made
and used in roleplay.

I thought i must type the kind of blocks like Grass or Stone! but its not right =)

So this is right:

/newlvl Test 128 64 128 flat

its just for MCSharp server!

sorry for my English =)

Edit:

Valid types are flat, pixel, island, mountains, forest, and ocean!

Also if you want to change the main level for something bigger say the 200's range make a new level called test.

Go to your levels folder cut and paste the Main.DAT level to outside of the levels folder

next Rename the Test.DAT to Main and it should work.

Other things to note is that you can make a Autoload.txt in your server folder and in that txt file type the name of the maps you want to load when you start the server.

This will load the named levels so you wont have to load them manually when you start the server.

This may also help you: http://www.minecraftwiki.net/wiki/MCsharp

Also check the Server Properties.txt file and read the top. This shows the Options you can change or add to the .TXT