OPen mdl file failed(Dspbuilder9.1+MATLAB2008B)

Your character encoding is set to GBK which is a chinese code page.

If you do what the error message suggests and type:

bdclose all; set_param(0,'CharacterEncoding', 'windows-1252')

you should be able to load the design. It seems in DSPB 9.1, the documentation for the Multipliy Add block was changed to use a special character that looks like a + on top of a - sign. This character unfortunately is not in the GBK codepage.

You can patch your DSPB installation by just loading the allblocks_altera_dspbuilder2.mdl file (using the MATLAB edit command), press CTRL+G and type in line 3729. Then move across to column to 321 (or thereabouts - the error message doesn't seem that accurate) and just delete (or replace with +/-) the special characters in

y = a0xb0 ± a1xb1 [+ a2xb2 [± a3xb3]]]

Then resave the file. Restart MATLAB to reset your character encoding and try again.