Pocket Excel spreadsheets were only produced by the original app for Windows Mobile and thus are fairly dated file type. Most spreadsheet programs had the ability to import or open .pxl files, but most of them cannot create it any more. So you probably won't find any software capable of xls to pxl conversion (Excel to Pocket Excel).
This conversion entry was verified by us and conversion was flagged as wrong or not possible.
Usually this happens when the conversion would try to convert different types of data between each other, such as audio to image, or it is not possible because incompatibility between programs, caused by closed file formats, very limited support etc.
If you find entry that you feel is flagged as bad wrongly, please tell us in the discussion below with as much as information as possible so we can fix it.