you have to decide
data or code
If you have invalid data, how do you want to handle it?
There is no fail-safe for all the possible problems that can happen, to deliver data you can call clean and sufficient.
So decide the number of errors to tolerate before rejecting the input and requiring better quality.
If your data in excel do have an intended structure, then use that structure information in a data step (or sql) with the DBSASTYPE option. This tells excel how to deliver the data. When they don't conform, you will get missing values and perhaps "invalid data" messages.
The online doc for DBSASTYPE
http://support.sas.com/documentation/cdl/en/acpcref/63184/HTML/default/viewer.htm#a002261324.htm