Per your linked CNN article, some key points:
Senate Minority Leader Mitch McConnell, R-Kentucky, had warned Democrats before the vote that his party would want to amend the bill -- possibly with hot-button issues like repealing the health care reform law or extending the Bush-era tax cuts for all income levels. Senate Majority Leader Harry Reid, D-Nevada, responded that those amendments were not germane to the bill and he would not allow votes on them.
Republican aides called attention to opposition by business groups like the U.S. Chamber of Commerce and the National Association of Manufacturers, who generally support Republicans.
The Politicususa article is a bit more direct in their opinion:
- Senate Republicans blocked the bill because they were angry that Harry Reid wouldn’t allow them to offer amendments. Senate Republicans blocked a bill that could have helped end the flow of jobs out of the country, because Mitch McConnell is still mad at Harry Reid.
So, on one level, it's due to just plain old politics. On a different level, it's petty personal bickering. Which, I guess, is plain old politics as well.
It could also be noted that Mitch McConnell opposes the bill more so than Republicans in general.