Craft Edge

Thanks to you all or the replies which sorted the problem out for me. However when i import the image into inkscape the windows become rounded and not square?

I wonder if anybody can help with this problem.see images converted in inkscape of showboat which when put into scal some of the lines move i have tried ungrouping the file but to no avail

As a newby i am not sure if i have don this right i hope if it is wrong then you my friends will put me right