In past I have asked a question about version 0.91 height and width fields are empty.
http://www.inkscapeforum.com/viewtopic.php?f=22&t=19580&p=74843#p74843
Further to that today found a solution and sharing.
Do as follows:
Object/Transform (Shift+Ctrl+M)
click on Scale. Height and Width can be monitored or maintained until the basic problem of 0.91 version is solved.

I thought sharing above will be helpful to others too.
nihon94