Truncated text fields in pivot table

My pivot table rerieves data from a query that loads data from a csv file.
The query brings upo the right data, however the pivot table doesn't.
1. Sometimes the fields are truncated to 253 chars -> this may be a
limitation of pivottables. Is there a way to overcome it??
2. Sometimes the field is empty, just a "V" appears or just the test
"Microsoft Excel" --> this I don't know why cause the text is not too long.

Any ideas?
Thanks
e.