python toolbox - def execute error

I am trying to make python toolbox. I used a converter to convert regular toolbox to python toolbox. It did the job, but I had to fix the code manually in some parts. When I did that, syntax was fine, but drop-down menu for selecting fields was missing. I managed to fix it, and get the menu. Code in which I get an error is working fine in regular toolbox, but not here. Here is the full code:

EDIT Whatever I do, I always get some kind of error in the "def execute" part of the code. I defined variables, and fixed the previous error. Error is for sure there in def execute part. This is the new code:

import arcpy

class Toolbox(object):
    def __init__(self):
        self.label = "Alat"
        self.alias = "Alat_replace"
        self.tools = [Alatko]

class Alatko(object):
    def __init__(self):
        self.label = "Label alata"
        self.description = "Insert znaka"
        self.canRunInBackground = True

    def getParameterInfo(self):
        # First parameter
        in_features = arcpy.Parameter(
            displayName="Input Features",
            name="in_features",
            datatype="Feature Layer",
            parameterType="Required",
            direction="Input")
        in_features.filter.list = ["Point"]

        # Second parameter
        field = arcpy.Parameter(
            displayName="Field Name",
            name="field_name",
            datatype="Field",
            parameterType="Required",
            direction="Input")

        field.parameterDependencies = [in_features.name]
        field.filter.list = ["Short","Long","Double","Float","Text"]

        # Third parameter
        sql = arcpy.Parameter(
            displayName="SQL_expres",
            name="SQL_Expression",
            datatype="SQL Expression",
            parameterType="Optional",
            direction="Input")

        sql.parameterDependencies = [in_features.name]

        # Fourth parameter
        Character = arcpy.Parameter(
            displayName="Charcters",
            name="Char_string",
            datatype="String",
            parameterType="Required",
            direction="Input")

        # Fifth parameter
        Position = arcpy.Parameter(
           displayName="PositionNR",
           name="Position",
           datatype="String",
           parameterType="Required",
           direction="Input")

        # Sixth parameter
        out_features = arcpy.Parameter(
           displayName="Output Features",
           name="out_features",
           datatype="Feature Layer",
           parameterType="Derived",
           direction="output")

        out_features.parameterDependencies = [in_features.name]

        params = [in_features, field, sql, Character, Position, out_features]
        return params

    def isLicensed(self):
        return True

    def updateMessages(self, parameters):
        in_features = parameters[0]
        field = parameters[1]
        sql = parameters[2]
        Character = parameters[3]
        Position = parameters[4]
        out_features = parameters[5]

    def execute(self, parameters, messages):
        in_features = parameters[0].valueAsText
        field = parameters[1].valueAsText
        sql = parameters[2].valueAsText
        Character = parameters[3].valueAsText
        Position = parameters[4].valueAsText
        out_features = parameters[5].valueAsText
        Position = int(Position)
        if Character == "#":
           cur = arcpy.UpdateCursor(table)
        else:
           cur = arcpy.UpdateCursor(table, Character)
        row = cur.next()
        while row:
            value = row.getValue(field)
            newValue = value[:Position] + Character + value[Position:]
            row.setValue(field, newValue)
            cur.updateRow(row)
            row = cur.next()
        del cur, row

The code imports specific characters into the field in desired position.

This is the window for input: feature class for input class Field name for field name I want to insert character sql for optional selection Character is for character I want to put in and positionNR is te number of position i want to put my character in

this is the example

and this is the error

New error is:

Traceback (most recent call last): File "", line 100, in execute NameError: global name 'table' is not defined