[galaxy-user] bed file error

Dear Galaxy users, I made a bed file from BAM for some farther analysis. Original BAM file could be nicely displayed in UCSC browser as well as in trackster. However, resulting bed file cannot be taken into UCSC-web page just stops loading without any message. Trackster returns message: "Dataset cannot be displayed due to an error" When I press "view error" button the page says "Killed". Is there any way to fix this? Best Aleks