Never used the scanner, but I may have seen the same problem...
Have you tried it with different pictures/documents? Have you tried with different scan settings?
I'm thinking that it's possible that the scanned image is just too big for your scanner or computer's memory. It is possible to set the quality settings so high that the PC can't process the scan completely... which could explain a partial, but not complete scan. I had this happen with a flat-bed scanner, so it didn't physically leave the document/picture out, but it did indeed fail to complete the scan until I lowered the settings.
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"If to err is human, then I must be some kind of human!" -Me