Excel - Startup Problem

Here is the problem summary. I'm trying to start Microsoft Excel from my computer and every time I start it, I get the following error;

Window Title: Microsoft Forms
Error Message: Could not load an object because it is not available on this machine.

A screen dump of the error is provided below

This problem comes, every time I start excel. Be it, trying to open an embedded excel object or excel directly. I've been living with this problem, trying to get over every time by clicking 'OK' until I felt it is too annoying to do and decided to get rid of the problem.

To start with, I tried the error message in Google, but cannot find a convincing solution to get rid of the issue.

I decided to get rid of this on my own and this is what I did.

1) Start Excel -> Navigate to Tools - Add ins

I unchecked on each and every available Add in and restarted Excel to see if that solved my problem. No luck :(. I got the same nice message after that as well.

2) Direction two: I navigated to the following path

c:\Documents and Settings\\Application Data\Microsoft\Excel\XLSTART

Here I found couple of .XLA files which are not listed in my "Add in" list.

3) I tried removing one at a time and restarted Excel every time I did this.

4) When I removed one of the add in, the problem disappeared. In my case, the add in was NitroPDF.xla.

5) When I removed this add in, and restarted Excel, it was working without any problems.

No errors this time :)