import problems : glm, uno, org.w3c.dom

[Heslau]

Hello guys,

I've seen the post about the following problem :
"The import glm cannot be resolved"

and I have the same issue + a couple more.
The import glm cannot be resolved
The type org.w3c.dom.Element is not accessible

I'm using Eclipse and experimenting with jogl (or at least trying to) but I failed to have the first tutorial working until now.
If anyone knows why and how it may happen, help would be welcome :/