Hi,
The location of the krb5.ini doesn't truly matter as long as it is correctly specified in Tomcat's java options and accessible by the account running the service. From the error, it looks as if there is a white space (blank) in between the folder and backslash:
Acquire TGT using AS Exchange
[Krb5LoginModule] authentication failed
Could not load configuration file C:\WINNT \Krb5.ini (The filename, directory name, or volume label syntax is incorrect)
Correct the file location in the java option to correctly point to the krb5.ini file (whether it's stored in C:/Windows or C:/WINNT), then restart Tomcat to enforce the change.
Regards,
Morgan