brush stroke breaks down

I need often a wavelike brush (I work in a corrugated board factory)for presentation material and created one with a half sine wave.
It works fine until picture is large enoug. Then the stroke breaks down to individual half wavelets with random orientation.
What is the problem? Computer memory? (Memory: 261 040 kb) OS? OS information: Microsoft Windows 2000)or what? (not XaraX I hope!)
Try the attached picture yourself

I need often a wavelike brush (I work in a corrugated board factory)for presentation material and created one with a half sine wave.
It works fine until picture is large enoug. Then the stroke breaks down to individual half wavelets with random orientation.
What is the problem? Computer memory? (Memory: 261 040 kb) OS? OS information: Microsoft Windows 2000)or what? (not XaraX I hope!)
Try the attached picture yourself

You do not appear to have attached the file.

Christine