When I open my files in calc the formulas are all different

Hello everyone!

I have a legal copy of Microsoft Office in my personal computer and always been happy with it, never gave me any trouble. But recently my computer broke and at the moment I am forced to work in two borrowed computers, with no microsoft office, that's why I started using LibreOffice portable.

At the moment I am having two problems that I can't find the answer to.

All my files are in xls or doc, because I also need them to be compatible with my bosses computer, who has no intention of changing.

1.
I have formulas refering to other spreadsheets in the same file, but when I open the file in LibreOffice portable, those formulas get a #REF error.

2.
I cannot copy a graph to the writer.
When I try, an object appears in the writer but no image.

I am not a computer expert, so if you coud please keep your answers simple and explain the solution clearly I would largely appreciate!

Thank you very much!