BUG #2149: can not enter M into a varchar field in version 8.1.1

The following bug has been logged online:

Bug reference: 2149
Logged by: Abigail Corrigan
Email address: abigail(dot)corrigan(at)pnl(dot)gov
PostgreSQL version: 8.1.1
Operating system: linux
Description: can not enter M into a varchar field in version 8.1.1
Details:

I get an error when trying to insert M into a varchar field in version
8.1.1 but it was working in version 7.4. The error leads me to think that
there is a different encoding on the dose_units field in the new database.
How do we encode the special character "" into a varchar field for version
8.1.1?

The error message is as follows:
Invalid UTF-8 byte sequence detected near byte 0xb5

Thanks!