int unsigned type mismatch

hello ,

In PHP I took a field in database as INT UNSIGNED
I am running many queries based on this field in my script
The problem is that it is running fine on localhost
but when uploaded to web server its not working.
sql statement is not fetching row, i think the field
is working as string because when i changed the field
to VARCHAR its working.
also i am adding 1 to this field without typecasting
it as INT it is working

please help me out. if someone have any suggestions, please help me ..
thanks
ankur bhatnagar