[IDCS2 Win]Problem Writing PMString to a text file using IPMStream!

Hi,

I want to write a PMString value into a text file.sometimes the string is written in the txt file & sometime it is not written in the file.Instead of writing the String i get some square boxes written in the file.Some times some special symbols like @,<,# etc gets written along with the boxes!I dont know why this is happening.

This is the code i have written:
PMString swatchName="";//String that i want to write in txt file
IDFile DetailsFile;//The txt file where i want to write
IPMStream * txtFileOutStream = StreamUtil::CreateFileStreamWriteLazy(DetailsFile,kOpenOut);
txtFileOutStream->Open();
swatchName.ReadWrite(txtFileOutStream);
txtFileOutStream->Close();

Plz tell where im going wrong.Help needed very urgent.

Thanks in advance