I have an archaeological inventory database I would like to relate to a site database feature class. I want every site to display an inventory of materials that were recovered from it. The inventory is a simple non-spatial xls table that contains numeric and text data mixed with some special characters such as '<>' , '/' , () , '-' , '"'. I created an empty table in the gdb that hosts the feature class. I used the inventory xls file as the field template and then used the 'Load data' geoprocess to import data from the same xls table using the 'input schema must match target schema' argument. This operation failed with an 'schema does not match' error. So I switched to manual matching and, unsurprisingly, could not find any mismatches between source and target schema. Upon running the process I, again, encountered an error. This time the geoprocessor was not happy with the content itself and refused to load data that looks like '123/456'. The entire data set is formatted as text because I already had problems with other data entries. I cannot change the symbology as the database entries have to match the physical labels on the associated archaeological material. Specific symbols have specific meanings on the label and I cannot create ambiguities between inventory and materials. I tried unsuccessfully to import from xls file as well as csv.
So, what is going on here and how can I fix it?