I just found why!
When you have a field that is > the the display length and ypu have a space the report form try to do a word rap of the field. Now if the option Stretch is not set then the line get cut.

>I have a report form with a field which is a file name and path.
>The field value is:

"C:\PROGRAM FILES\WINCORAD\ZCV\IGIFPOAS.D"

>Now in my report form it display like this

"C:\PROGRAM"

>
>if I transform my field with this

strtran(MyField," ","-")

than if see the all field with spaces replace with "-".
>
>Why this report form work this way?