Player model Weight probelm

Hello,

(I already posted this message in the Gmod section, but it still without solutions)

I made custom player models since some months,
but recently I had a problem :

http://img15.hostingpics.net/pics/294326gmflatgrass0001.jpg

and

http://img15.hostingpics.net/pics/558997gmflatgrass0008.jpg

On the first screenshot, the legs are detached from the torso
I heard this is a problem about “weight” but I’ve searched for a long time and I never found how to solve this problem.

I hope you’ll can help me, have a good day !
(Sorry if I don’t speak english very well, but this is not my first language)

EDIT :
this is the code I found in the console when I choose this player model :


MountainDivision\DivisionMale07.mdl/player\male_anims.mdl : missmatched parent bones on "ValveBiped.Bip01_Pelvis"
MountainDivision\DivisionMale07.mdl/player\male_anims.mdl : missmatched parent bones on "ValveBiped.Bip01_Spine"
MountainDivision\DivisionMale07.mdl/humans\male_gestures.mdl : missmatched parent bones on "ValveBiped.Bip01_Pelvis"
MountainDivision\DivisionMale07.mdl/humans\male_gestures.mdl : missmatched parent bones on "ValveBiped.Bip01_Spine"
MountainDivision\DivisionMale07.mdl/humans\male_postures.mdl : missmatched parent bones on "ValveBiped.Bip01_Pelvis"
MountainDivision\DivisionMale07.mdl/humans\male_postures.mdl : missmatched parent bones on "ValveBiped.Bip01_Spine"
MountainDivision\DivisionMale07.mdl/player\male_anims.mdl : missmatched parent bones on "ValveBiped.Bip01_Pelvis"
MountainDivision\DivisionMale07.mdl/player\male_anims.mdl : missmatched parent bones on "ValveBiped.Bip01_Spine"

Please I really need your help

For the first screenshot it seems to be a weighting problem, what modeling software do you use? For the second screenshot I think I had a similar problem before but I cannot remember what I did to solve it.