Denis,
I had errors with collating sequence before.
What happened was that we installed a Chinese language interpreter software to enable our VFP app to use chinese characters.
We did a reindex when the Chinese Interpreter (CI) app was running.
When we shut down the CI and run the app, the error message "collating sequence pin yuen.... not found" will appear. Restarting the CI software solve the problem.
To resolve the error permanently, we switched off the CI, deleted all cdx files from Dos Prompt, and did a reindex.
After which, we were able to run the app without the CI app in the background.
HTH.
Yau