Can’t Select a View on Informix

I'm using Informix IDS 11.50 Innovator-C edition running on Slackware Linux 12.0. I've been running a very small Database on it(less than 10000 records on the biggest table).

I'm trying to select a view from a web service, and every time there's a high load user load queries are being dropped with messages like:

ERROR [HY000] [Informix .NET provider][Informix]Could not write to a temporary file

Or

ERROR [HY000] [Informix .NET provider][Informix]Could not open or create a temporary file

The Web Service is using the .NET Informix Driver which relies on the Informix ODBC API.

Searching for those errors on the web or in the online documentation I found that it's something related to DBTEMP environment variable and the DBSPACETEMP configuration parameter.

Both are set. DBTEMP pointing to a directory with all permissions(rw), three dbspaces are listed on DBSPACETEMP. One regular dbspace and two flagged as temporary dbspace.

Storage is not a problem, the directory and the dbspaces have a lot of free space left.
The tables that the view Targets use R-tree indexes, and those are stored on a dedicated dbspace. One more thing I'm using a Geodetic Datablade on the database.