Well, I never found a cause for the error, but I rewrite the query to join on a different field and that worked. The field I was trying to...

And then there is the CLR version that comes in with the following results on my machine:

========== Recursive CTE ==========

Table 'Worktable'. Scan count 2, logical reads 600002, physical reads 0,...

Does anyone consider the use of a CLR function for this type of processing?

For example:

[Microsoft.SqlServer.Server.SqlFunction]

public static int clr_occurs2(string target, char lookFor)

{

...