Question about multivariate regression results

I'm a PhD candidate working with my dissertation data in organizational theory. I'm having trouble understanding my data results and have a few questions.

1) In running a multivariate regression with Likert data, I have some data with 4-point Likert scales and some 5-point scales. Does this matter for analyzing the data?

2) I'm finding statistically signficant correlations between the dependent variable and several of the independent variables. However, my regression does not result in any statistically significant variables. I'm not sure why this is, especially given that the scatterplots seem to show a linear relationship between several of the independent variables and the dependent variable. I've checked for multicollinearity using VIF and tolerance and my values for tolerance range from .3 to .8 and VIF from 1.2 to 3.1 leading me to believe that multicollinearlity is not a problem. Am I missing something? Do you have any suggestions for what could be going wrong or what I'm doing wrong with my data? Or any suggestions for different ways to analyze the data?

If you need more details, please let me know. Thanks!!!