INDEX EXCALIBUR

We use Excalibur Index for full text search, but get this errors on several delete/update/insert at the same time. Since a few weeks, we have to drop indexes and recreate them a least one time per day, and the informix support seams to be unable to give us a solution. Have someone already have this sort of problem ? Thanks a lot IUS V 9.14.UC4-1 on solaris 2.6 Exception from Informix: XUET69:-937:Error (Sql -999, Isam -999) in writing to a file in (etxgl_delete_index). Exception from Informix: XIX000:-245:Could not position within a file via an index. Exception from Informix: XIX000:-244:Could not do a physical-order read to fetch next row.