importing XML

Hi new here and couldn't seem where to post this, I hope in here is ok.
Real new at copybots and have a really wierd problem and I can't seem to find any info on this paticular issue.
Most files I export as .xml that I can seem to get to work without crashing, res up invisible.
If you edit and and select the invisible objects you can see they are there but they are not visible, the viewer even reports the existance of the prims.
I have tried the same files multiple times and get the same results.
I have been successful on a few things so I know it does work, just not correctly some times.
I have compared the xml files of the ones that work and the ones that are invisible and the file structure appears the same just different values.
I am not very good at xml so even if there was something wrong I wouldn't be able to spot it more then likely.
So if any of you experienced goons out there could help a brother out, I would relly appriciate it, cause I have no idea what the deal is.
Is there something I need to change in the xml file maybe?