We are aware of this problem. Fonts with automatic ligatures, such as Calibri, Palatino, Linotype, Adobe Jensen Pro, and Myriad Pro, can fail to export certain character sequences to PDF, EPS, SVG, and AI (Illustrator) formats. Some of the failed sequences include 'ff', 'fl', 'fi', and 'Th'. The characters may fail to appear in the export file, and text following the character sequence may appear garbled. This problem occurs on Windows XP when regional settings are set for non-English text input, and occurs on all versions of Windows Vista and Windows 7. The nimbus tracking number for this is NIM012587. We have narrowed this to a Microsoft bug and we are actively working on a solution. I will post an update when a fix is available.