Is it possible to change (for example) the yTrans-value for more than one keyframe in one time? Or must I change them one by one? 
Working with the Walkdesigner that is quit a job.
I hope someone can help me with this.

Eddy Loonstijn, Netherlands

Poser comes with some Python scripts that will do the job. Choose Window->Python scripts, click the Utility button, and there's two scripts, DropFigAllFrames and DropActorAllFrames.

There's also my WalkThisWayV2 python script in freestuff, if you want to have your character walk on another surface than the ground plane. WalkThisWayV2 can deal with non-flat surfaces too.

You may find that this tutorial will give you exactly the information you require.
http://www.philc.net/tutorial7.htm

Hope that helps.

Wonderful how quck and helpful both of your responses are! Thanks a lot!

Overigens, landgenoot, houd ik ook van eten, maar moet ik helaas me ook steeds weer beperken om op lijn te blijven. ;-)

Phil's tutorial is invaluable knowledge for an animator. For the sake of completeness I'd like to point out another method I sometimes use to adjust the hight of a character to which a a walk cycle has been applied. As you know, applying a walk cycle drops the character to the ground. After applying the walk cycle load a poser square prop, set 'Visible' off in the props 'Properties', set the 'Set Figure Parent' to be the square. In frame one, adjust the yTran of the square so that the character is at the desired hight. The character will maintain this hight throughout the animation. If desired you can vary the hight of the square throughout the animation (probably best to use linear interpolation for the square if doing this). You are not limited to yTran, you can set x or z tran, or you can yRotate the square so that the character walks off in a diffrent direction, you can even rotate the square so that the character walks on a wall or ceiling. Note that if you apply a new walk cycle the character will drop to the floor again.

Wow, LesBentley!
This really is a very good way to handle this problem!
BTW, it reminds me of the frequent and very clever use of Null-layers in Adobe AfterEffects.
I will surely use your method, also because it makes adjustment very easy and variable.
Thanks, Eddy