Ignore the "unexpected character" error messages.
What's happening is that some older apps save their preferences by writing files into ~/Library/Preferences. This is understandable, since for a long time the operating system gave developers no help and only the vaguest guidance about how they should remember user preferences. Each developer had to come up with their own scheme.
OS X does now provide CFPreferences (in Core Foundation) and NSUserDefaults (the Cocoa equivalent), which automatically do all the grunt work, including saving values to files. All the files they create are stored in ~/Library/Preferences or /Library/Preferences, and are always written as property list files.
Developers who put together a working solution long ago, before CFPreferences/NSUserDefaults came along, continue to use it, even if it means they have to read/write the files themselves. ("If it ain't broke...") Many of them put their files in ~/Library/Preferences give them a .plist extension (because at the time that seemed to be what they were supposed to do) even though they were not actually in property list format. Nothing's actually broken. Those programs aren't using the newfangled preferences frameworks, so it doesn't matter what format their files are in.
Utilities like DW or TTP scan ~/Library/Preferences and report "unexpected character" for every file that isn't in property list format. The character may be unexpected by the utility, but not by the program that uses the file.
Just ignore the error. Everything is working fine.
