Help me hunt down my error

I wrote a layer handling script and for the most part it works. However
there are a few drawings (maybe 1%) that crash.

I get this error:

;error: Exception occurred: 0xC0000005 (Access Violation)

with this alert:
FATAL ERROR: Unhandled Access Violation Reading 0x6c617624 Exception at
65176876h

How can I make it catch the errors and tell me what they are so I can
try and figure out why these specific drawings are not working? the
portion of the script that is failing uses regular lisp, no vl.


I believe the following function may be the culprit, but I am not yet sure:

(if (/= LayerColor "-")
(progn
(if (= LayerFreeze "thaw")
(command "T" layer)
(command "F" layer))
(command "C" LayerColor layer)
(if (/= LayerLineType "Continuous")
(command "LT" LayerLineType layer))
(if (= LayerLock "unlock")
(command LayerLock layer))
(if (/= LayerLineWeight ".010")
(command "LW" LayerLineWeight layer))
(if (= 0 (getvar "PSTYLEMODE"))
(command "PS" LayerPlotStyle layer))
(if (= LayerPlot "noplot")
(command "P" LayerPlot layer))))

thanks for any help - kemp

 

I didn't see anything inherently wrote with the lisp file.
When it fails, it is probably because one of the variables is set to nil.
When I get frustrated with an error, I sometimes will add a princ statement
to show the values.
set SHOWVALS to T, when the program crashes to find the variable set to nil.
(if CHECKERROR
(progn
(princ "\nLayer = ")(princ Layer)
(princ "\nLayerFreeze = ")(princ LayerFreeze)
(princ "\nLayerColor = ")(princ LayerColor)
(princ "\nLayerLineType = ")(princ LayerLineType)
(princ "\nLayerLock = ")(princ LayerLock)
(princ "\nLayerLineWeight = ")(princ LayerLineWeight)
(princ "\nLayerPlotStyle = ")(princ LayerPlotStyle)
(princ "\nLayerPlot = ")(princ LayerPlot)
)
)

 

Thanks for both of your help. They are actually making me work right now
so I won't be able to test out your suggestions for a couple of days but
I will certainly post my findings later.

Thanks again, kemp