pkgver should really be a number - though I'm not sure what to do about this given your project doesn't have release numbers. Maybe you should create one, such as 0.1
If you comment out the arch line, arch will be detected automatically, so it will build as x86_64 on a 64-bit system
Package description should be like this, with no blank lines:
"caja-dropbox (an application to do whatever)"
"caja-dropbox can be described over several
"lines as follows and does this, that and the other"
This is a good news: i'm waiting the Mate version... But, i have another question: do i have to change something in the package if i want to submit it for the next salix release or I have to change it only if they'll change the source?
That looks fine to me. If you're going to submit it for 14.1, you may need to find somewhere to upload the files where they can be linked to directly, and add a sourcetemplate line to the SLKBUILD saying where they are. Have a look at people.salixos.org to see some examples. You can request space for your packages there, if you like.
Where a package needs to be rebuilt for a new Salix edition, it's a good idea to bump the pkgrel just to make sure anyone upgrading from (say) 14.0 to 14.1 will get the new package. But where there is a new version of the package, you go back to 1. If rebuilding is not needed, the package can be transferred as is.
Somewhere among the packaging guidelines there are instructions for submitting a package to sourceforge.
The repositories will close to new submissions when Salix xfce 14.1 is released, but since this is a Maté package and Maté isn't available yet from the repositories, never mind as a Salix flavour, you could probably submit it later. With no caja available yet, it really doesn't make sense to submit it now.
EDIT I see caja *is* in the 14.1 repositories, but it's called mate-file-manager. And of course, you will need to submit a 64 bit package alongside the i486 one.
).