First, I would really suggest downloading a newer version of PSQL. PSQL v11 is available at http://pervasivedb.com/psqlv11/Pages/Default.aspx. PSQL v7 was released in 1998. PSQL v11 offers several tools and methods for exporting data.
Second, if you have DDFs you should be able to create an ODBC DSN pointing to the DDFs and data files. Once you have an ODBC DSN, you can use just about any ODBC tool to export the data. If you use PSQL v11, you can even export to CSV (although it might be called SDF) from the Pervasive Control Center by right clicking on the table, selecting Export Data and following the wizard. If you want to automate exporting the tables or export more than one table at a time, you'll need a different tool. There are several out there.
The DDF files are a set of special files that describe the data files. The minimum files needed are FILE.DDF, FIELD.DDF, and INDEX.DDF. If you don't have these files, you'll need to know the record layout for each table / file. You can use DDF Builder, included with PSQL v11, to build the DDFs for your tables.