Heat maps is good, but it doesn't tell you if the user "missed" to click the tab or just didn't want to click it. Solutions is very straight forward and used by companies such as Microsoft and IBM. Users of your site probably know what to find there.
We have to look at the problem from a different angle and check the convertion rates. Do you have lower convertion rates on items in the solution tab, than on the product tab? If the answer is true, and the items on the solution tab are as wanted and equal in price as product items then we have a real problem.
Even if we have identified a problem, or suspect we have a problem with the tab label, it is possible to do an open card sort, where users group items together and label them by themselves. It could be a start, and its always nice to know what your users think.
Edit: One other suggestion, if card sort is not an option. You have six categories in the top menu, but you could easely narrow them down to five by moving the Contact Us to be a sub item of About Us. It is not unusual to see contact info within the about us group. Then you have only five top items which would be easier for the user to scan. I would move the About Us last and come up this order of navigation items:
Products | Solutions | Partners | Resources | About Us