error in fitT.do_fit() function

[ubutnux]

trying to run examples/fit_kepler37.py

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-29-1a412d7b2cf0> in <module>()
----> 1 fitT.do_fit()

/usr/local/lib/python2.7/site-packages/ktransit/fittransit.pyc in do_fit(self)
    193             [pdic[k] for k in self.fitparplanet]]
    194         fitpars = np.r_[fitvalstar,fitvalplanet]
--> 195         self.fitout = optimize.leastsq(self.ret_lstsq,fitpars,full_output=True)
    196         self.make_fitoutdicts()
    197 

/usr/local/lib/python2.7/site-packages/scipy/optimize/minpack.pyc in leastsq(func, x0, args, Dfun, full_output, col_deriv, ftol, xtol, gtol, maxfev, epsfcn, factor, diag)
    385             maxfev = 200*(n + 1)
    386         retval = _minpack._lmdif(func, x0, args, full_output, ftol, xtol,
--> 387                                  gtol, maxfev, epsfcn, factor, diag)
    388     else:
    389         if col_deriv:

TypeError: Cannot cast array data from dtype('O') to dtype('float64') according to the rule 'safe'