Hello,Chris,Thank you very much.I  try to do what you said,and at the matlab prompt,I typed 
'which spm' and 'which prt',no error:
>> which prt
D:\MATLAB\R2012a\toolbox\pronto\pronto_v1.1_beta\prt.m
>> which spm
D:\MATLAB\R2012a\toolbox\pronto\spm8_updates_r5236\spm.m
But when I  launch it with 'spm fmri' at the matlab prompt,it showed:
>> spm fnri
Error using spm_check_installation>check_basic (line 85)
There appears to be some problem with the installation.
The original spm8.zip distribution should be installed
and the updates installed on top of this.

Error in spm_check_installation (line 25)
check_basic;
Error in spm (line 333)
spm_check_installation('basic')
   

Thanks again.