How I Can check or increase the UDP or TCP buffer size, and what size is recommended ?

Try the following regkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Afd\Parameters \DefaultReceiveWindow (REG_DWORD) = 16384 (decimal)

If you are using the MS supplied ftp command line client it has a default buffer size of 4K.  You need to specify -w ##### to specify a different buffer size:

   ftp -w 32120

is an example of setting the buffer size to 32120.

   I increase the buffer size in a variety of ways (as was said by the experts comments), but I have
the same result:   ftp: bind: no buffer space supported.

 One clue more is that when I re-start the system, the first time I can use the FTP, for a while,
and sudddenly freeze. If I kill this window and open another new command window, and I enter
ftp with some address, the result is the above message.

  After a reboot process,  (some 10-20 minutes), the FTP fails almost all the times, whenever I used or not before the ftp command once the reboot process is completed.

Wow, searching on EE is amazing.  I found this problem from a couple of years ago.  It eems that this problem has nothing to do with the ftp data buffer size, but with the amount of memo available on the system.

     http://www.experts-exchange.com/Operating_Systems/Q_20561572.html

  The memory in the system is 1 Gb, and the OS is Windows XP Professional SPK 2. I can use all the
programs in a normal way in  the PC, and I can get a fast answer, and 'normal' behaviour in almost all of them. In reality there are three windows programs running all the time......and a variety of small DOS-console programs builded with Visual C. This small programs together with Windows XP Task Scheduller, makes possible send out, via ftp ,the captured to my office in an automatically way.
 
  The system is designed to  monitor weather and oceanographic sensors coupled in a sea structure. I can reach the system via remote using VPN. The system is collecting data evey 10 minutes,
and send out, via ftp, the last group of data captured, to a server in my office. Every time Ithe system sends out the volume of data , is less than 100 Kb.

  For almost a year, the system works O.K., and all the things in the PC are O.K., ..... but one day i get
the FTP BIND BUFFER message. Intermmitent with  a god behaviour of FTP, in average once a day and for a few minutes. So 95% percent the programs use the FTP, returns with FTP: BIND message,
and 5% of the times works O.K.

    It is possible that some external connection is failing, and there is the cause of the problem ???,
or definitivly is related to a system problem ????

In this sense memory does not mean RAM, it referring to specify "type" of memory used for specify types of buffers.

Based on the other post it could be due to too many programs running at the same time that attempt to use this same memory/buffer pool.

Are you getting entries in your event log?

Pretty dumb question, but have you rebooted yet to clear the memory?

      I tried all the sugerences, with a lot of reboots, but the results all the time were the same.
So, my last chance was to recover the system to the last backup I made with Acronis.
This was October 2007.

      After the recovering the ftp script programs are working well.