Table count Fatal error: Exit code 1

Hi!
I am trying to use Table count accordingly to this tutorial: Reference-based RNA-Seq data analysis
Everything goes well, but computing Z-score with Table count ends up with the following:
Fatal error: Exit code 1 ()
Traceback (most recent call last):
File “/usr/local/lib/python3.8/site-packages/pandas/core/ops/array_ops.py”, line 142, in _na_arithmetic_op
result = expressions.evaluate(op, left, right)
File “/usr/local/lib/python3.8/site-packages/pandas/core/computation/expressions.py”, line 235, in evaluate
return _evaluate(op, op_str, a, b) # type: ignore[misc]
File “/usr/local/lib/python3.8/site-packages/pandas/core/computation/expressions.py”, line 69, in _evaluate_standard
return op(a, b)
TypeError: unsupported operand type(s) for -: ‘str’ and ‘float’

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File “./table_compute.py”, line 342, in
out_table = fun(data)
File “”, line 2, in fun
File “/usr/local/lib/python3.8/site-packages/pandas/core/ops/init.py”, line 419, in f
new_data = self._combine_frame(other, na_op, fill_value)
File “/usr/local/lib/python3.8/site-packages/pandas/core/frame.py”, line 6065, in _combine_frame
new_data = self._dispatch_frame_op(other, _arith_op)
File “/usr/local/lib/python3.8/site-packages/pandas/core/frame.py”, line 6018, in _dispatch_frame_op
bm = self._mgr.operate_blockwise(right._mgr, array_op)
File “/usr/local/lib/python3.8/site-packages/pandas/core/internals/managers.py”, line 374, in operate_blockwise
return operate_blockwise(self, other, array_op)
File “/usr/local/lib/python3.8/site-packages/pandas/core/internals/ops.py”, line 54, in operate_blockwise
res_values = array_op(lvals, rvals)
File “/usr/local/lib/python3.8/site-packages/pandas/core/ops/array_ops.py”, line 189, in arithmetic_op
res_values = _na_arithmetic_op(lvalues, rvalues, op)
File “/usr/local/lib/python3.8/site-packages/pandas/core/ops/array_ops.py”, line 149, in _na_arithmetic_op
result = _masked_arith_op(left, right, op)
File “/usr/local/lib/python3.8/site-packages/pandas/core/ops/array_ops.py”, line 91, in _masked_arith_op
result[mask] = op(xrav[mask], yrav[mask])
TypeError: unsupported operand type(s) for -: ‘str’ and ‘float’

Does anybody know how to overcome this problem?