Why not just:
ON ERROR ll=.f.
release o
o=CREATEOBJECT("MSXML2.DOMDOCUMENT.4.0")
on error
if type("o")#"O"
* Class definition MSXML2.DOMDOCUMENT.4.0 is not found".
endif

>How can I detect if the MS XML is installed?
>
>I want to prevent the error "Class definition MSXML2.DOMDOCUMENT.4.0 is not found".
>
>Thanks in advance.
>
>--rab