An Excel file needs an Excel file processor (or Excel itself) to read it. Did you study the Excel file format documentation to learn how to read and process them and write such a processor? …or download such a utility from the web?
I have a database file named ACCPTH on my system. If I FTP it to your system, how would you know what to do with it? Ideally, I would FTP it as a savefile that you could restore. In effect, that would bring a kind of “processor” along with it — the file description itself that would provide the info to DB2 to let it know where the boundaries between fields are, what the data types and lengths are, what CCSIDs are involved and everything else that might be needed.
An Excel file has all of that included but not in any form that DB2 can understand. You need to provide the routines that can read the formatting info and apply to the data. (Some of the “formatting” is simply in knowing the general structure.}
Also, you need to ensure that your system is properly configured to receive such files from other (ASCII?) systems. For example, you should start by verifying that your QCCSID system value is not set as 65535 but rather for your correct CCSID (probably 37). Even if you have everything needed to process the Excel format, the bit patterns of every byte that gets transferred to your system need to be converted according to their intended encodings.
If you don’t have any Excel processors, start by reviewing Read MS Excel files with Java and Apache POI – the Java API for Microsoft Documents to get initial info.