The cable u used to connect to pc might be CA-42/DKU-5 cable. 
Parallel connections (such as PC suite connectivity + RConnect) are not supported by 
this kind of cable. 
And since you can only connect this phone with either of above 2 cables only,  
it's not possible to use both functionalities at the same time.   
But u don't have to uninstall pc suite at all to use either one. 
Just go to the "Manage Connections" options in PC suite and uncheck the checkbox 
in front of your cable type. 
Then u'll be able to use RConnect without uninstalling PC suite. 
Next time u want to use pc suite, just check on the appropriate cable type and you 
are done. 
Regards.