Wow, that is probably the most succinct request for support I’ve ever seen! 
Firstly, some assumptions.. I’m assuming by Lightroom v1.4, you mean, v4.4 and I’m assuming that you are exporting a selection of images using a standard Hard Drive export preset. With very little to go on, I would suggest:
- Try a different export preset e.g. For email
- Try different export preset settings e.g. Change the export location, enable/disable image sizing etc
- Restore your export preferences via Edit > Preferences > Presets > Lightroom Defaults > Restore Export Presets
- Reset your LR preferences file: Lightroom 4 Preferences.agprefs (search the community for instructions on how to do this)
- Re-install LR
- Reach out to the Adobe tech support team