Memory Allocate Error

New to this forum and hope some one can help. I have two computers that are running the same operating system - Windows 2000 Pro. Both computers have at least 25GB of free hard drive space. Both computers have 512MB of RAM and both are running at least a 1.4Ghz Processor. Both computers have a licensed copy of Photoshop 6.0.1. Photoshop works fine as long as I do not use the scanner. Both computers have a UMAX 2400S scanner attached to them. The UMAX software that is loaded is the VistaScan32 V3.55. The Windows Page file size on both is set to at least 384MB.

Okay, here is the problem, on both of these units when I open PhotShop, click Import and choose the VistaScan32 V3.55 to scan in an image, the VistaScan launches okay, but then when I click the Preview to scan an image, I can hear the scanner initialize but then receive the following error:
Memory Allocate Error Contact he systems administrator. Sorry, I am the Administrator. Everything looks fine in Windows and I can't find any other evident problems.

Does any one have any ideas?

Thanks you in advance.