How much RAM do you actually have though? Regardless of how big your hard drive is (250GB) and how much free space it has, it sounds like you are running out of RAM. While the system can and will use hard drive space for virtual memory, not everything can be swapped out to virtual memory. Every program has core code that must reside in RAM only, so even if you have lots of swap space, the program is having problems because acutal running code is memory limited.
Open activity monitor (in your utilities folder) and look at how your memory is being used - http://support.apple.com/kb/HT1342
Look at the Free and Wired portions. In the example in that Kb article, the system has 2GB of actual RAM installed. If the Free section was very small, and the Wired was taking up nearly all of that space, then the system would be running out of RAM for active processes. The only solution then is to install more RAM.
Looks like it to me - with only 2GB you seem to be really just running out of space. What model of MacBook is it? You can look up your model at Apple:
And you can see how much RAM you could put in it at
http://eshop.macsales.com/shop/apple/memory/ - Depending on your model of MacBook, you may be able to go up to 6GB or even 8GB which would likely make a huge difference in your system and performance.
P.S. OWC's recommendation may be more then what Apple offically says it can take. But that is because the Apple specs are based solely on what was available to go in it at the time of manufacture. OWC actually does their own inhouse testing of what is currently available, and works, in those systems. They guarantee what they sell will work in the machines they say it will.
Mid 2009 says up to 4GB
Looks like that's what si needed and I appreciate your assistance. this has solved it.
Note though that OWC has that model being capable of using up to 6GB if you want to go that far (a mix of one 2GB module and one 4GB module).
Just be sure to get RAM that comes with a lifetime warranty, and that the manufacturer guarantees with your specific machine (Apple computers often do not work well with generic or budget RAM modules). If not OWC, other good companies are crucial and kingston (NOT their valueRAM line though, but the machine specific modules their web site will find for you).