matrix error in wave fitting?

 singular matrix or other numeric error.

I don't understand the error and it should not show this when fitting a curve or am I missing something?

Function Rishabhsircronicles(w,x) : FitFunc
	Wave w
	Variable x
	variable	k,ka,k1,k2
	k=(7.64*(10^-(12))) //ka =0.00000000000764
	ka=225
	variable p,q
	p=((k/2)*(ka/x))
	q=((k/3)*(ka/x))
	
	//CurveFitDialog/ These comments were created by the Curve Fitting dialog. Altering them will
	//CurveFitDialog/ make the function less convenient to work with in the Curve Fitting dialog.
	//CurveFitDialog/ Equation:
	//CurveFitDialog/ f(x) = f(x) = w+a*((2/exp(h/(2*kb))*(w/T))+1)+b*(1+(2/((exp(h/(3*kb))*(w/T))-1))+(3/(exp((h/(3*kb))*(w/T))-1)^2)
	//CurveFitDialog/ End of Equation
	//CurveFitDialog/ Independent Variables 1
	//CurveFitDialog/ x
	//CurveFitDialog/ Coefficients 2
	//CurveFitDialog/ w[0] = a
	//CurveFitDialog/ w[1] = b
	k1=(w[0]*(	(	2/(exp(p)	-1)	)	+1	)	)
	k2=	(w[1]*(	1+  (	2/(	exp(	q)-1	)	)	+	(	3/((exp(q) - 1	)^2)  )	)	)
	
	return ka+K1+K2
	
End