Troubleshooting Object Reference Not Set to Instance of an Object

[Guest]

I am logging errors in my web application in a database for troubleshooting (and emailing them to myself) and I am getting this error I cannot understand

I have a click event that is generating an "Object reference not set to instance of an object". Now, I have seen this error a lot and usually I am forgetting to create a new instance or something... but the puzzling thing in this case -- is that I have tested this click event several times and I do not see this error. I am guessing it has something to do with the users browser or session settings or something. But I cannot determine what. One thing that is odd... is that in the server variables there is an odd line shown under the user-agent that I do not understand.

From the 'ALL_HTTP' Server variable --
HTTP_USER_AGENT:Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1
HTTP_~~~~~~~:~~~~:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
HTTP_~~~~~~~~~~~~~~~:~~~~~ ~~~~~~

Server Variable: 'HTTP_USER_AGENT' has the value: 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)
Server Variable: 'HTTP_~~~~~~~' has the value: '~~~~:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Server Variable: 'HTTP_~~~~~~~~~~~~~~~' has the value: '~~~~~ ~~~~~~~

Whenever I see those squigglies that is when I seem to get errors on the click event. Any ideas as to what it means? I have tested the site with my own IE6 browser and I am not getting the error. Any ideas what to check

Thanks
Lori

 

[Ken Cox [Microsoft MVP]]

Hi Lori,

It looks like someone is adding non-standard headers to the post.

It may be an effort to create a buffer overrun, or it may be just foreign
characters that means something in that language.

You might want to check your IIS logs to see if you can correlate the source
IP and trace it back.

 

[Guest]

I just got the same error..... this time with some different server variable

Server Variable: 'HTTP_USER_AGENT' has the value: 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322)
Server Variable: 'HTTP_WEFERER' has the value: 'IVOTQNQEMSFDULHPQQWOYIYZUNNYCGPKYLEJGDGVCJVTLBXFGGMEPYOQKEDOTWFAOBUZXUWLSZLKBRNVW

I have no idea what HTTP_WEFERER is

Would someone adding non-standard headers effect the view state at all

I will try and trace the IP back.

 

[MS News \(MS ILM\)]

One of your users has Norton Personal Firewall and it is munging the HTTP
headers.

I am logging errors in my web application in a database for

troubleshooting (and emailing them to myself) and I am getting this error I
cannot understand.

I have a click event that is generating an "Object reference not set to

instance of an object". Now, I have seen this error a lot and usually I am
forgetting to create a new instance or something... but the puzzling thing
in this case -- is that I have tested this click event several times and I
do not see this error. I am guessing it has something to do with the users
browser or session settings or something. But I cannot determine what. One
thing that is odd... is that in the server variables there is an odd line
shown under the user-agent that I do not understand.

From the 'ALL_HTTP' Server variable -->
HTTP_USER_AGENT:Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)
HTTP_~~~~~~~:~~~~:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~
HTTP_~~~~~~~~~~~~~~~:~~~~~ ~~~~~~~

Server Variable: 'HTTP_USER_AGENT' has the value: 'Mozilla/4.0

(compatible; MSIE 6.0; Windows NT 5.1)'

Server Variable: 'HTTP_~~~~~~~' has the value: '~~~~:~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~'
Server Variable: 'HTTP_~~~~~~~~~~~~~~~' has the value: '~~~~~ ~~~~~~~'

Whenever I see those squigglies that is when I seem to get errors on the

click event. Any ideas as to what it means? I have tested the site with my
own IE6 browser and I am not getting the error. Any ideas what to check?