What format is the data file in? I would ask on an MS Office or Excel forum regarding splitting the data into each line segment in Excel.

Once you have split the data into segments (make sure there is a unique identifier for each polyline) and loaded the file into MapInfo you can follow the instructions here http://testdrive.mapinfo.com/techsupp/miprod.nsf/kbase_by_product/704C383D587B1F848525654D006DA6E3 to create lines from your data.

Now you've got a bunch of individual line segments for each polyline you can use Table > Combine Objects using Column..., specifying the unique identifying column and checking the data aggregation settings to ensure you carry over the data correctly, to combine your line objects into polyline objects.

Probably best to do the combine into a new table.

Depending on what format the data file is in, I would ask on an MS Office or Excel forum regarding splitting the data into each line segment in Excel.

Once you have split the data into segments (make sure there is a unique identifier for each polyline) and loaded the file into MapInfo you can follow the instructions here http://testdrive.mapinfo.com/techsupp/miprod.nsf/kbase_by_product/704C383D587B1F848525654D006DA6E3 to create lines from your data.

Now you've got a bunch of individual line segments for each polyline you can use Table > Combine Objects using Column..., specifying the unique identifying column and checking the data aggregation settings to ensure you carry over the data correctly, to combine your line objects into polyline objects.

Probably best to do the combine into a new table.