The workaround does solve the problem when I have encountered it. However, to extend on information regarding the problem, I've noticed that it happens whenever I transfer a project using the Excel Set Cell Color and Background.vi to a computer with a new installation of LabVIEW. This project is not an executable. My experience has been with LV 2010 and 2011 (including SP1). This project does use the Report Generation Toolkit vi's. All computers have been Win7.
I'm adding some images of the parts of the vi when broken and fixed. It might be useful to note that the vi opens with the dirty dot already there after a fresh install.
Also just experienced the same problem with a project. Exact same project on another PC has no problems. When I tried to build on my laptop, a broken VI was found and that killed the build.
The broken VI was the Excel Set Cell Color and Border.vi. Relinking the Invoke node solved the problem. Kudos to you Ching-Hwa_Yu, Google found your post here.
I haven't seen a definitive reason for why this happens. The original PC was also running LV 2011 but it did not have any version of Excel installed. My laptop has the same version of LabVIEW, but it also has Excel 2010 installed.