Vahan,
That probably has to do with the type of variable being entered. In your constant one, it appears you're using an integer as the ClickItem parameter which is, essentially, pointing to the index on the combo box. In the table one, you're reading data out of a table which, depending upon the table source, might be getting interpreted/cast as a string instead of an integer. In fact, the log message appears to be saying such because the 2 is wrapped in quotes indicating that it's looking for a string.
You might want to double check your table data and make sure that the column in question is being indicated as an integer and not a string. The other way to handle it is to have the ClickItem be passed a code expression where you're wrapping that table data with a StrToInteger call to make sure it's being clicked as a integer.