ERROR: AV's and IWButton.picture.data: the parameter is incorrect

[MrSpock]

The problem started when we were 3-4 users at the same time. Whether trying the same or different forms, we all experiences the problems with AV and picture.data error described above.

Notice: I'm not (deliberately, or as far as I know) using threads.

Just as a little background, IW uses multiple threads.  There is a new thread with each response from a client/browser.  A click or other action from the browser launches a thread on the server.  That thread processes the event until it finishes (ex: returns a response to the browser).

So, if two users simultaneously call the same code that is not thread safe then you'll have multiple threads using thread unsafe code.

Dan

That needs more explanation.

I have some variables declared as session variables but almost all of them are declared in the implementation part of the unit. For example I create bmp: TBitmap in form onCreate and remove it in form onDestroy. I expect the bmp variable to be different for each user. All forms, while creating them, should, as I expect, belong to the user's session. So the bmp should be independent for each user connected at the same time to a different session. But now I see the same variable is shared between users, which should not happen. When I use
TIWForm1.Create(WebApplication).Show
in fact user2 gets the same implementation part variables as user1 has got. User1 sees variables of user2 and vice versa!!

But moving a number of variables from many forms to usersession unit does not make sense, does it? This way intraweb is of no use to me.