Just recently installed Lubuntu 12.10 on my Samsung N130 netbook, and left-clicking only works every once in a while. Here is the output from synclient, if it helps. Before changing MaxTapTime to 0, tapping to click worked fine. Clicking with hardware button worked fine on previous versions of Ubuntu before switching to Lubuntu on same computer.

Parameter settings:
LeftEdge                = 1775
RightEdge               = 5503
TopEdge                 = 1652
BottomEdge              = 4662
FingerLow               = 25
FingerHigh              = 30
FingerPress             = 256
MaxTapTime              = 0
MaxTapMove              = 245
MaxDoubleTapTime        = 180
SingleTapTimeout        = 180
ClickTime               = 100
FastTaps                = 0
EmulateMidButtonTime    = 75
EmulateTwoFingerMinZ    = 282
EmulateTwoFingerMinW    = 7
VertScrollDelta         = 111
HorizScrollDelta        = 111
VertEdgeScroll          = 0
HorizEdgeScroll         = 0
CornerCoasting          = 0
VertTwoFingerScroll     = 1
HorizTwoFingerScroll    = 0
MinSpeed                = 1
MaxSpeed                = 1.75
AccelFactor             = 0.0359131
TrackstickSpeed         = 40
EdgeMotionMinZ          = 30
EdgeMotionMaxZ          = 160
EdgeMotionMinSpeed      = 1
EdgeMotionMaxSpeed      = 445
EdgeMotionUseAlways     = 0
TouchpadOff             = 0
LockedDrags             = 0
LockedDragTimeout       = 5000
RTCornerButton          = 2
RBCornerButton          = 3
LTCornerButton          = 0
LBCornerButton          = 0
TapButton1              = 1
TapButton2              = 3
TapButton3              = 0
ClickFinger1            = 1
ClickFinger2            = 1
ClickFinger3            = 0
CircularScrolling       = 0
CircScrollDelta         = 0.1
CircScrollTrigger       = 0
CircularPad             = 0
PalmDetect              = 0
PalmMinWidth            = 10
PalmMinZ                = 200
CoastingSpeed           = 20
CoastingFriction        = 50
PressureMotionMinZ      = 30
PressureMotionMaxZ      = 160
PressureMotionMinFactor = 1
PressureMotionMaxFactor = 1
ResolutionDetect        = 1
GrabEventDevice         = 1
TapAndDragGesture       = 1
AreaLeftEdge            = 0
AreaRightEdge           = 0
AreaTopEdge             = 0
AreaBottomEdge          = 0
HorizHysteresis         = 27
VertHysteresis          = 27
ClickPad                = 0