Hello,
Your error message is the one I receive when I try to use a sqlite3 file with sqlite2 or vice et versa.
Use the command "file xxx.sdb" to find the type of sqlite [2/3] it is, and verify which sqlite you are using.
The command "sqlite -version" return the version as expected. Be careful that "sqlite" (no 2 neither3) is sometimes associated with one or the other. There is not much difference between them, except that they store the data in different format that are 100% incompatible!. Much better to always call the version explicitly.
In the (very improbable) case that your sdb file is in the wrong format, you can easily change it to the right one by dumping the data using the corresponding version of sqlite ( .output MyData.sql <cr> .dump) to write the data in readable format, then reading back with the correct sqlite (Most probably sqlite3 < MyData.sql).
Regards, Paul