Negative decimal numbers haskell

Possible duplicate:
Negative doubles or floats in Haskell (macports)

I am new to haskell, and when I try to enter negative floating point numbers (like -1.0) in ghci or use them in modules, I keep getting segmentation errors.

How can I give negative floating point values ​​to variables without generating seg errors?

My apologies early, if this is a complete question about the Nob, but I'm kind of shocked, it's as difficult as it is ...