[TYPO3-english] Parse error: powermail - swiftmailer

[Stephan Bernhard]

hi list

this is not a cross-posting!
since no one answers in the german forums, i try it here.

after updating to TYPO3 4.5.10 there is an error message when sending a 
powermail form in FE:

Parse error: syntax error, unexpected '<' in 
/.../typo3/contrib/swiftmailer/classes/Swift/Mime/Headers/DateHeader.php 
on line 119

updating powermail from 1.5.7 to 1.6.4 didn't change anything (unlike 
other threads have reported). php version 5.2.17.


what does this error mean?
how can i correct it?

thanks for any help and hint
stephan