Diff between XVID0036 and XVID0037

Hello,

I've a Philips DVD player (DVP630 with the lastest firmware 1109).
I can read some XVID films and some not. All are seen without any problem on 
a PC.

I've check the files with gspot and the XVID I can't read have all the 
string XVID0037 in the user data displayed by GSPOT.

I've seen a thread dealing with openDML container but it doesn't matter for 
me : I read well films in both modes : AVI 1.0 and in AVI 2.0 (open DML).

The only difference i've seen is the number after XVID (but I perhaps miss 
others difference as the gspot window show a lot of infos).

What is the difference between XVID0037 and XVID0036 (or less) ?
Is there another program than gspot I can use to check the difference 
between 2 files ?

Thanks by advance for your advice,

Lancien