finally got the printer to work!
my discovery applies to general printer issue, for those who are interested, here comes what I did:
1. install cups extension
2. install cups-dev extension
3. download gutenprint-5.2.8-pre1.tar.bz2 from
http://sourceforge.net/projects/gimp-print/files/gutenprint-5.2/5.2.8-pre1/4. open terminal as root, and type (the following steps are for creating an extension)
export CFLAGS="-march=i486 -mtune=i686 -Os -pipe"
export CXXFLAGS="-march=i486 -mtune=i686 -Os -pipe"
export LDFLAGS="-Wl,-O1"
tar xjvf gutenprint-5.2.8-pre1.tar.bz2
cd gutenprint-5.2.8-pre1
./configure --prefix=/usr/local
make -j3
make DESTDIR=/tmp/package install
cd /tmp
mksquashfs package gutenprint-5.2.8.tcz
5. browse to /tmp/package/, you will see a file gutenprint-5.2.8.tcz, this is the extension for all gutenprint-5.2.8 priinter drivers, including MP250.
6. copy gutenprint-5.2.8.tcz to /mnt/sda3/tce/optional/ (sda3 is me root, yours could be different).
7. load gutenprint-5.2.8.tcz and make it OnBoot.
8. open Opera and goto
http://localhost:631 to start CUPS user interface.
9. click on Add Printer
10. CUPS will ask you for password
11. when asked for password, open a term.inal and type: sudo passwd
12. type 123 as password and confirm again
13. switch back to Opera and login CUPS as root
14. if everything goes right, you should see your printer listed, select your printer, click continue.
15. select the model of your printer, click continue
16. click "set options"
17. now you should be able to see the printer under "Printers"
18 click your printer name and select "print test page" under "Maintenance"
19 enjoy the sound of printing, because I sure did.